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LogTape changelog ​

Version 2.0.1 ​

Released on January 20, 2026.

@logtape/otel ​

  • Fixed OpenTelemetry sink to preserve nested object structures in attributes instead of converting them to JSON strings. This follows the OpenTelemetry specification which supports map<string, AnyValue> for nested objects. [#135]

    Before this fix, nested objects were serialized as JSON strings:

    logger.info("Event", { workspace: { id: 42, name: "test" } });
// OpenTelemetry attribute: workspace = '{"id":42,"name":"test"}'

    After this fix, nested objects are preserved as structured data:

    logger.info("Event", { workspace: { id: 42, name: "test" } });
// OpenTelemetry attribute: workspace = { id: 42, name: "test" }

    This allows OpenTelemetry backends (like Axiom, Honeycomb, etc.) to properly query and filter on nested properties (e.g., workspace.id = 42).

    • Error objects in properties (when exceptionAttributes is "raw" or false) are now serialized as structured objects instead of JSON strings, preserving properties like name, message, stack, cause, and custom properties.

Version 2.0.0 ​

Released on January 15, 2026.

@logtape/logtape ​

  • Added lazy() function for deferred evaluation of contextual properties. This allows properties passed to Logger.with() to be evaluated at logging time rather than at with() call time. [#131]

    import { getLogger, lazy } from "@logtape/logtape";

let currentUser: string | null = null;
const logger = getLogger("app").with({ user: lazy(() => currentUser) });

logger.info("Action");  // logs with user: null
currentUser = "alice";
logger.info("Action");  // logs with user: "alice"
    • Added Lazy<T> type to represent a lazy value.
    • Added isLazy() function to check if a value is a lazy value.

  • Added Error overloads for Logger.error(), Logger.warn()/Logger.warning(), and Logger.fatal() as a shorthand for logging errors as structured properties. The default message template for logger.error(error) (and the corresponding warning/fatal overloads) is {error.message}. Note that logger.warn(new Error(...)) and logger.fatal(new Error(...)) may result in slightly different output compared to previous versions, where this looked like a {*} (properties-only) shorthand. [#123]

  • Improved JSON Lines formatter serialization of Error and AggregateError values in properties so that name, message, stack, cause, and errors are preserved in JSON output. [#123]

  • Added "none" and "disabled" options for AnsiColorFormatterOptions.timestamp to disable timestamp display, consistent with TextFormatterOptions. [#120, #121 by Jonathan Wilbur]

    • Added "none" and "disabled" to the timestamp option type.
    • Changed the custom timestamp formatter return type to string | null (was string).
    • Fixed getAnsiColorFormatter() to properly handle null timestamps instead of rendering "null" with ANSI styling.

  • Added lineEnding option to text and JSON Lines formatters for Windows compatibility. [#113 by Joonmo]

  • Replaced the deprecated unload event with pagehide for automatic disposal in browser environments. [#79, #124, #125 by Pavel Semiklit]

    The unload event is deprecated and will be removed from browsers (starting with Chrome in 2025). It also prevents pages from being eligible for browser back/forward cache (bfcache), which significantly impacts navigation performance. The pagehide event fires at nearly the same timing as unload but is bfcache-compatible and more reliable on mobile browsers.

    Note that Deno continues to use the unload event since it does not support pagehide.

  • Added FingersCrossedOptions.bufferLevel option to configure which severity levels are buffered separately from the trigger level. [#126]

    • When set, only log records at or below bufferLevel are buffered.
    • Records above bufferLevel but below triggerLevel pass through immediately without buffering.
    • Throws RangeError if bufferLevel is greater than or equal to triggerLevel.

  • Added Logger.isEnabledFor() method to check if a log level would be processed by the logger. [#129]

    • Returns true if the level is at or above lowestLevel and at least one sink is configured to receive logs at that level.
    • Useful for conditionally executing expensive computations before logging, particularly for async operations where lazy evaluation callbacks cannot be used.

  • Added async callback support for lazy evaluation of structured data. [#129]

    • All logging methods (trace(), debug(), info(), warn(), warning(), error(), fatal()) now accept async callbacks that return Promise<Record<string, unknown>>.
    • When an async callback is passed, the method returns Promise<void>.
    • The async callback is only invoked if the log level is enabled; if disabled, the callback is never called and the returned Promise resolves immediately.
    • Added corresponding overloads to Logger interface and LogMethod interface.

@logtape/adaptor-log4js ​

  • Added a new package @logtape/adaptor-log4js for integrating LogTape with log4js logging infrastructure. [#57]

    • Added getLog4jsSink() function to forward LogTape log records to log4js loggers.
    • Added Log4jsSinkOptions type (discriminated union) for configuring the adapter behavior with type-safe context strategy options:
    • Added install() function for convenient auto-configuration with custom log4js logger and configuration options.
    • Added categoryMapper option to customize how LogTape categories are mapped to log4js categories (default: join with dots).
    • Added contextStrategy option to control how LogTape properties are handled:
      • "mdc" (default): Use log4js MDC (Mapped Diagnostic Context)
      • "args": Pass properties as additional arguments to log methods
    • Added contextPreservation option for MDC strategy to control handling of existing log4js context:
      • "preserve" (default): Save and restore existing context
      • "merge": Merge LogTape properties with existing context
      • "replace": Replace existing context with LogTape properties
    • Maps LogTape log levels to equivalent log4js levels (trace, debug, info, warn, error, fatal).
    • Supports dynamic logger creation based on LogTape categories or using a fixed log4js logger instance.
    • Enables seamless adoption of LogTape-enabled libraries in applications using log4js without requiring logging infrastructure changes.

@logtape/config ​

  • Added a new package @logtape/config for configuring LogTape from plain objects. [#117]

    • Added configureFromObject() function to configure LogTape from plain JavaScript objects loaded from JSON, YAML, TOML, or other formats.
    • Added module reference syntax (module#export()) for specifying sinks, filters, and formatters.
    • Added built-in shorthands for common sinks and formatters (#console(), #text(), #ansiColor(), #jsonLines()).
    • Added ConfigureOptions interface with shorthands and onInvalidConfig options.
    • Added onInvalidConfig option for graceful error handling:
      • "throw" (default): Throw ConfigError on invalid configuration
      • "warn": Apply valid parts and log warnings to meta logger
    • Added expandEnvVars() utility function for environment variable expansion with ${VAR} and ${VAR:default} syntax.
    • Added LogTapeConfig, SinkConfig, FilterConfig, FormatterConfig, LoggerConfig, and ShorthandRegistry interfaces.
    • Added ConfigError class for configuration errors.
    • Added DEFAULT_SHORTHANDS constant with built-in shorthand mappings.

@logtape/elysia ​

  • Added a new package @logtape/elysia for Elysia integration. [#111]

    • Added elysiaLogger() function to create Elysia plugin for HTTP request logging.
    • Supports predefined formats (combined, common, dev, short, tiny) compatible with Morgan.
    • Supports custom format functions returning string or structured objects.
    • Supports configurable log levels via level option.
    • Supports request skipping via skip option.
    • Supports immediate logging mode via logRequest option.
    • Supports Elysia plugin scopes via scope option (global, scoped, local).
    • Logs errors at error level via onError hook.

@logtape/otel ​

  • Removed the attributes. prefix from property keys when converting LogTape properties to OpenTelemetry attributes. Properties are now sent with their original key names as flat attributes, which aligns with standard OpenTelemetry conventions and prevents double nesting (e.g., attributes.attributes.method) in OpenTelemetry backends. [[#127], #130]

    • Changed convertToAttributes() to use property keys directly without adding an attributes. prefix.
    • This is a breaking change: existing users with queries or dashboards that rely on the attributes.* key names will need to update them to use the new flat key names (e.g., attributes.method becomes method in the attributes field).

  • Added exceptionAttributes option to control how Error objects in properties are handled. [#123]

    • "semconv" (default): Follows OpenTelemetry semantic conventions for exceptions, converting Error objects to exception.type, exception.message, and exception.stacktrace attributes.
    • "raw": Serializes Error objects as JSON strings with their properties (name, message, stack, cause, errors) preserved.
    • false: Treats Error objects as regular objects (typically results in empty objects).

    IMPORTANT

    This is a behavior change: Error objects in properties now follow semantic conventions by default instead of being serialized as JSON strings. If you need the previous behavior, set exceptionAttributes: "raw".

  • Fixed primitive type preservation in attributes: numbers and booleans are now preserved as their original types instead of being converted to strings.

@logtape/file ​

@logtape/windows-eventlog ​

  • Improved Windows Event Log message formatting using NELOG_OEM_Code (3299) from netmsg.dll. [#115 by Roland Kaufmann]

    • Changed default event ID to NELOG_OEM_Code (3299), which provides a generic message format that properly displays log messages in Windows Event Viewer.
    • Added formatter option to WindowsEventLogSinkOptions for custom text formatting of log records.
    • Refactored FFI implementations (Deno, Node.js, Bun) to use a common WindowsEventLogFFI interface.
    • Added documentation for registering netmsg.dll as an event message file in the Windows Registry.

Version 1.3.6 ​

Released on January 7, 2026.

@logtape/cloudwatch-logs ​

  • Fixed getCloudWatchLogsSink() to properly close internally created CloudWatchLogsClient connections on disposal. Previously, when the sink created its own client (i.e., when options.client was not provided), the client's TLS connections were not closed, causing resource leaks that were detected by Deno's stricter resource leak checking in newer versions.

Version 1.3.5 ​

Released on December 19, 2025.

@logtape/redaction ​

  • Fixed a regression where Error, Date, RegExp, and other built-in objects were incorrectly converted to empty objects {} when processed by redactByField() and redactByPattern(). These objects are now preserved without modification. [#114]

Version 1.3.4 ​

Released on December 18, 2025.

@logtape/redaction ​

  • Fixed redactByField() to use redacted property values for all message placeholders, not just those directly matching field patterns. Previously, named placeholders like {args} would use original values even when containing nested sensitive fields (e.g., args[0].email), exposing sensitive data in the log message. [#99]

Version 1.3.3 ​

Released on December 18, 2025.

@logtape/redaction ​

  • Fixed redactByField() to recursively process arrays, ensuring that sensitive fields inside objects within arrays are properly redacted. Previously, arrays were not traversed, so sensitive data in nested structures like { args: [{ email: "..." }] } would not be redacted. [#99]

Version 1.3.2 ​

Released on December 18, 2025.

  • Reduced npm package sizes by excluding unnecessary source files from published packages. Previously, the src/ directory was included in npm packages, which increased download sizes without providing runtime value. [#112]

Version 1.3.1 ​

Released on December 16, 2025.

@logtape/otel ​

  • Fixed a bug where log records sent during lazy initialization were silently dropped. Now, log records are buffered during initialization and emitted once the OpenTelemetry logger provider is ready. [#110]

  • Added OpenTelemetrySink interface which extends Sink with ready property and AsyncDisposable.

  • Added OpenTelemetrySink.ready property, a Promise<void> that resolves when lazy initialization completes. For sinks created with an explicit loggerProvider, this resolves immediately.

Version 1.3.0 ​

Released on December 15, 2025.

@logtape/logtape ​

  • Added context-based category prefix feature for library hierarchies. [#98]

    • Added withCategoryPrefix() function to prepend category prefixes to all log records within a callback context.
    • Uses the existing contextLocalStorage configuration, so no additional setup is required if implicit contexts are already enabled.
    • Useful for SDKs that wrap internal libraries and want to show their own category in logs from those libraries.
    • Prefixes accumulate when nested, allowing multi-layer architectures.

@logtape/drizzle-orm ​

  • Added @logtape/drizzle-orm package for Drizzle ORM integration. [#104]

    • Added getLogger() function to create a Drizzle ORM-compatible logger.
    • Added DrizzleLoggerOptions interface for configuration.
    • Added DrizzleLogger class implementing Drizzle's Logger interface.
    • Logs queries with structured data: formattedQuery (with parameter substitution), query (original), and params (original array).

@logtape/express ​

  • Added @logtape/express package for Express.js HTTP request logging using LogTape as the backend. [#105]

    • Added expressLogger() function to create Express middleware for request logging.
    • Added ExpressLogTapeOptions interface for configuration.
    • Added RequestLogProperties interface for structured log properties.
    • Added FormatFunction type for custom format functions.
    • Added PredefinedFormat type for Morgan-compatible format names.
    • Supports predefined formats: combined, common, dev, short, tiny.
    • Supports custom format functions returning strings or objects.
    • Supports skip function to conditionally skip logging.
    • Supports immediate option to log on request arrival vs response.

@logtape/fastify ​

  • Added @logtape/fastify package for using LogTape as Fastify's logging backend. [#102]

    • Added getLogTapeFastifyLogger() function to create a Pino-compatible logger wrapper for Fastify's loggerInstance option.
    • Added FastifyLogTapeOptions interface for configuration.
    • Added PinoLikeLogger interface implementing Pino's logger contract.
    • Added PinoLogMethod interface for Pino-style log method signatures.
    • Added PinoLevel type for Pino log levels.
    • Supports all Pino method signatures: string messages, object + message, object-only, and printf-style interpolation (%s, %d, %j, %o).
    • Implements child(bindings) method using LogTape's Logger.with().

@logtape/hono ​

  • Added @logtape/hono package for Hono HTTP request logging using LogTape as the backend. [#107]

    • Added honoLogger() function to create Hono middleware for request logging.
    • Added HonoLogTapeOptions interface for configuration.
    • Added HonoContext interface for context type compatibility.
    • Added RequestLogProperties interface for structured log properties.
    • Added FormatFunction type for custom format functions.
    • Added PredefinedFormat type for Morgan-compatible format names.
    • Supports predefined formats: combined, common, dev, short, tiny.
    • Supports custom format functions returning strings or objects.
    • Supports skip function to conditionally skip logging.
    • Supports logRequest option to log on request arrival vs response.
    • Cross-runtime compatible: works on Cloudflare Workers, Deno, Bun, and Node.js.

@logtape/koa ​

  • Added @logtape/koa package for Koa HTTP request logging using LogTape as the backend. [#106]

    • Added koaLogger() function to create Koa middleware for request logging.
    • Added KoaLogTapeOptions interface for configuration.
    • Added KoaContext interface for context type compatibility.
    • Added RequestLogProperties interface for structured log properties.
    • Added FormatFunction type for custom format functions.
    • Added PredefinedFormat type for Morgan-compatible format names.
    • Supports predefined formats: combined, common, dev, short, tiny.
    • Supports custom format functions returning strings or objects.
    • Supports skip function to conditionally skip logging.
    • Supports logRequest option to log on request arrival vs response.

@logtape/otel ​

  • Added support for gRPC and HTTP/Protobuf protocols for OTLP log export. [#103]

    • Added @opentelemetry/exporter-logs-otlp-grpc dependency for gRPC protocol support.

    • Added @opentelemetry/exporter-logs-otlp-proto dependency for HTTP/Protobuf protocol support.

    • Protocol is determined by environment variables following the OpenTelemetry specification:

      1. OTEL_EXPORTER_OTLP_LOGS_PROTOCOL (highest priority)
      2. OTEL_EXPORTER_OTLP_PROTOCOL (fallback)
      3. Default: "http/json" (for backward compatibility)

    • Added OtlpProtocol type for protocol values ("grpc", "http/protobuf", "http/json").

    • Uses dynamic imports to maintain browser compatibility when gRPC is not used.

  • Added OpenTelemetrySinkExporterOptions.additionalResource option to merge custom resource attributes with the default resource. [#108 by Nils Bergmann]

    This allows adding attributes like ATTR_DEPLOYMENT_ENVIRONMENT_NAME without providing a custom loggerProvider:

    import { getOpenTelemetrySink } from "@logtape/otel";
import { resourceFromAttributes } from "@opentelemetry/resources";
import { SEMRESATTRS_DEPLOYMENT_ENVIRONMENT } from "@opentelemetry/semantic-conventions";

getOpenTelemetrySink({
  serviceName: "my-service",
  additionalResource: resourceFromAttributes({
    [SEMRESATTRS_DEPLOYMENT_ENVIRONMENT]: "production",
  }),
});

  • Refactored OpenTelemetrySinkOptions to a discriminated union type for better type safety.

    • Added OpenTelemetrySinkProviderOptions interface for providing a custom LoggerProvider (recommended for production use).
    • Added OpenTelemetrySinkExporterOptions interface for automatic exporter creation based on environment variables.
    • loggerProvider and exporter options (serviceName, otlpExporterConfig) are now mutually exclusive at the type level.

  • Changed the exporter initialization to use lazy loading. The exporter is now created asynchronously when the first log record is emitted, rather than synchronously when getOpenTelemetrySink() is called. This allows the main API to remain synchronous while supporting dynamic imports for protocol selection.

  • Added automatic fallback to no-op logger when no OTLP endpoint is configured. This prevents repeated transport errors when environment variables like OTEL_EXPORTER_OTLP_ENDPOINT or OTEL_EXPORTER_OTLP_LOGS_ENDPOINT are not set and no URL is provided in the exporter configuration.

@logtape/redaction ​

  • Fixed a security vulnerability where redactByField() and redactByPattern() could enter an infinite loop when processing objects with circular references, leading to a denial-of-service (DoS) attack. The redaction functions now correctly handle circular references, preventing stack overflows.

  • Fixed a security vulnerability where sensitive data in class instances was not being redacted. The redaction logic now recursively processes class instances, ensuring that sensitive fields are redacted regardless of the object's structure.

@logtape/sentry ​

  • Enhanced Sentry sink with modern observability features including automatic trace correlation, breadcrumbs, and structured logging support. [#90]

    • The getSentrySink() function now accepts an optional SentrySinkOptions object instead of a Sentry client instance. The old pattern getSentrySink(getClient()) still works with a deprecation warning.
    • Added automatic trace correlation with active Sentry spans (trace_id, span_id context).
    • Added enableBreadcrumbs option to create breadcrumbs for all log events.
    • Added beforeSend hook to transform or filter records before sending.
    • Added automatic structured logging support via Sentry's Logs API (SDK v9.41.0+ with enableLogs: true).
    • Added ParameterizedString support for better message grouping in Sentry.

@logtape/syslog ​

Version 1.2.6 ​

Released on January 7, 2026.

@logtape/cloudwatch-logs ​

  • Fixed getCloudWatchLogsSink() to properly close internally created CloudWatchLogsClient connections on disposal. Previously, when the sink created its own client (i.e., when options.client was not provided), the client's TLS connections were not closed, causing resource leaks that were detected by Deno's stricter resource leak checking in newer versions.

Version 1.2.5 ​

Released on December 18, 2025.

@logtape/redaction ​

  • Fixed redactByField() to use redacted property values for all message placeholders, not just those directly matching field patterns. Previously, named placeholders like {args} would use original values even when containing nested sensitive fields (e.g., args[0].email), exposing sensitive data in the log message. [#99]

Version 1.2.4 ​

Released on December 18, 2025.

@logtape/redaction ​

  • Fixed redactByField() to recursively process arrays, ensuring that sensitive fields inside objects within arrays are properly redacted. Previously, arrays were not traversed, so sensitive data in nested structures like { args: [{ email: "..." }] } would not be redacted. [#99]

Version 1.2.3 ​

Released on December 18, 2025.

  • Reduced npm package sizes by excluding unnecessary source files from published packages. Previously, the src/ directory was included in npm packages, which increased download sizes without providing runtime value. [#112]

Version 1.2.2 ​

Released on November 29, 2025.

@logtape/redaction ​

  • Fixed redactByField() to properly redact sensitive fields in objects passed via the {*} wildcard placeholder. Previously, the original object reference was kept in the message array, exposing sensitive field values even when they were redacted in properties. [#99]

Version 1.2.1 ​

Released on November 28, 2025.

@logtape/redaction ​

  • Fixed redactByField() to also redact sensitive values in the message array, not just in properties. Previously, sensitive field values were exposed in the log message even when the corresponding property was redacted. [#99]

Version 1.2.0 ​

Released on November 11, 2025.

@logtape/logtape ​

  • Added support for nested property access in message template placeholders, enabling direct access to nested objects, arrays, and complex data structures without manual property extraction. [#91, #93 by 伍闲犬]

    • Dot notation: {user.name}, {order.customer.profile.tier}
    • Array indexing: {users[0]}, {users[0].name}
    • Bracket notation with quotes: {user["full-name"]}, {data["a.b c"]}
    • Escape sequences in quoted strings: \", \', \\, \n, \t, \r, \b, \f, \v, \0, and Unicode escapes (\uXXXX)
    • Optional chaining: {user?.profile?.email}, {data?.items?.[0]?.name}
    • Combined patterns: {users[0]?.profile?.["contact-info"]?.email}
    • Enhanced security: blocks access to __proto__, prototype, and constructor at any depth to prevent prototype pollution

  • Added context-based isolation for fingers crossed sink to handle scenarios like HTTP request tracing where logs should be isolated by implicit context values. [#86]

    • Added isolateByContext option to FingersCrossedOptions for isolating buffers based on specified context keys from log record properties.
    • Context isolation can be combined with existing category isolation for fine-grained control over buffer flushing behavior.
    • Each context buffer maintains separate trigger states and size limits, preventing unrelated logs from being flushed together.
    • Added memory management options for context isolation to prevent memory leaks in high-traffic applications: bufferTtlMs for time-based cleanup, cleanupIntervalMs for configurable cleanup intervals, and maxContexts for LRU-based capacity limits. TTL and LRU can be used independently or together for comprehensive memory management.

  • Changed the type of the TextFormatterOptions.value callback to accept a second parameter that provides access to the default cross-runtime inspect() function, making it easier to implement custom value formatting with fallback to default behavior.

    • Changed the type of TextFormatterOptions.value to (value: unknown, inspect: (value: unknown, options?: { colors?: boolean }) => string) => string (was (value: unknown) => string).
    • The second parameter is optional and can be ignored for backward compatibility.
    • Users can now customize formatting for specific value types while falling back to the cross-runtime inspect() function for others, without needing to reimplement the complex runtime detection logic.

@logtape/pretty ​

  • Added support for getters and showProxy options in inspectOptions to allow fine-grained control over how objects and proxies are displayed. These options are available in Node.js, Deno, and Bun runtimes, providing consistent behavior across platforms. [#95]

@logtape/redaction ​

  • Extended field-based redaction to recursively redact sensitive fields in objects nested within arrays, providing more comprehensive protection for structured data. [#94]

Version 1.1.8 ​

Released on January 7, 2026.

@logtape/cloudwatch-logs ​

  • Fixed getCloudWatchLogsSink() to properly close internally created CloudWatchLogsClient connections on disposal. Previously, when the sink created its own client (i.e., when options.client was not provided), the client's TLS connections were not closed, causing resource leaks that were detected by Deno's stricter resource leak checking in newer versions.

Version 1.1.7 ​

Released on December 18, 2025.

@logtape/redaction ​

  • Fixed redactByField() to use redacted property values for all message placeholders, not just those directly matching field patterns. Previously, named placeholders like {args} would use original values even when containing nested sensitive fields (e.g., args[0].email), exposing sensitive data in the log message. [#99]

Version 1.1.6 ​

Released on December 18, 2025.

@logtape/redaction ​

  • Fixed redactByField() to recursively process arrays, ensuring that sensitive fields inside objects within arrays are properly redacted. Previously, arrays were not traversed, so sensitive data in nested structures like { args: [{ email: "..." }] } would not be redacted. [#99]

Version 1.1.5 ​

Released on December 18, 2025.

  • Reduced npm package sizes by excluding unnecessary source files from published packages. Previously, the src/ directory was included in npm packages, which increased download sizes without providing runtime value. [#112]

Version 1.1.4 ​

Released on November 29, 2025.

@logtape/redaction ​

  • Fixed redactByField() to properly redact sensitive fields in objects passed via the {*} wildcard placeholder. Previously, the original object reference was kept in the message array, exposing sensitive field values even when they were redacted in properties. [#99]

Version 1.1.3 ​

Released on November 28, 2025.

@logtape/redaction ​

  • Fixed redactByField() to also redact sensitive values in the message array, not just in properties. Previously, sensitive field values were exposed in the log message even when the corresponding property was redacted. [#99]

Version 1.1.2 ​

Released on October 22, 2025.

  • Fixed Vercel Edge Runtime compatibility issue where LogTape caused “Node.js API is used (process.on) which is not supported in the Edge Runtime” error during configuration. Implemented defense-in-depth approach with both EdgeRuntime global variable detection and dynamic bracket notation access (proc?.["on"]) to avoid static analysis detection while ensuring runtime safety. [#92]

Version 1.1.1 ​

Released on September 18, 2025.

@logtape/pretty ​

  • Fixed a bug where logs with long property keys would cause the formatter to fail, resulting in no output being displayed. The issue occurred when property keys exceeded the indentation width, causing negative padding calculations that threw a RangeError. [#87]

Version 1.1.0 ​

Released on September 11, 2025.

@logtape/logtape ​

  • Added “fingers crossed” logging feature that buffers debug logs in memory and only outputs them when a trigger event occurs, reducing log noise while preserving context for debugging. [#59]

    • Added fingersCrossed() function that implements the fingers crossed logging pattern with support for trigger levels, buffer management, and category isolation.
    • Added FingersCrossedOptions interface for configuring fingers crossed behavior with options for trigger level, buffer size, and category isolation modes.

  • Added Logger.emit() method for emitting log records with custom fields, particularly useful for integrating external logs while preserving their original timestamps. [#78]

@logtape/file ​

  • Changed getStreamFileSink() to implement AsyncDisposable instead of Disposable.

  • Fixed flaky behavior in high-volume logging scenarios where some log records could be lost during sink disposal. The sink now ensures all data is fully written to disk before disposal completes.

@logtape/pretty ​

@logtape/sentry ​

  • Changed the type of the getSentrySink() function to accept any Sentry client implementing the public capture APIs (was (client?: Client) => Sink). Introduced a structural SentryClientLike interface to avoid nominal type conflicts across differing @sentry/core instances. [#80 by Sora Morimoto]

  • Fixed preservation of Sentry template metadata by returning a ParameterizedString from the internal getParameterizedString() so that captureMessage receives the templated form and breadcrumbs/formatting can leverage __sentry_template_* metadata. [#80 by Sora Morimoto]

  • Fixed cross-runtime compatibility by removing an unnecessary node:util type import referenced only by documentation, avoiding module resolution issues outside Node.js. [#80 by Sora Morimoto]

Version 1.0.6 ​

Released on October 22, 2025.

  • Fixed Vercel Edge Runtime compatibility issue where LogTape caused “Node.js API is used (process.on) which is not supported in the Edge Runtime” error during configuration. Implemented defense-in-depth approach with both EdgeRuntime global variable detection and dynamic bracket notation access (proc?.["on"]) to avoid static analysis detection while ensuring runtime safety. [#92]

  • Changed getStreamFileSink() in @logtape/file package to return Sink & AsyncDisposable instead of Sink & Disposable for proper asynchronous stream cleanup. The previous synchronous disposal did not wait for streams to finish flushing data to disk, causing incomplete writes in high-volume logging scenarios and resource leaks. The new async disposal properly waits for both the stream ‘finish’ event and file handle closure, ensuring all data is written and resources are cleaned up correctly.

Version 1.0.5 ​

Released on September 10, 2025.

  • The satellite packages (@logtape/file, @logtape/otel, @logtape/redaction, @logtape/sentry, and @logtape/syslog) now properly specify version compatibility constraints for their peer dependency on @logtape/logtape, ensuring consumers install compatible versions of the core package.

Version 1.0.4 ​

Released on July 6, 2025.

  • Fixed a bug where the optimized code paths in getJsonLinesFormatter() did not output newline characters between JSON objects, violating the JSON Lines specification. This completes the fix that was partially addressed in version 1.0.3.

Version 1.0.3 ​

Released on July 6, 2025.

  • Fixed a bug where jsonLinesFormatter and the formatter returned by getJsonLinesFormatter() did not output newline characters between JSON objects, violating the JSON Lines specification that requires one JSON object per line.

Version 1.0.2 ​

Released on July 4, 2025.

  • Fixed Vercel Edge Functions compatibility issue where LogTape caused Node.js API warnings due to process.on usage detection. Refactored process access to use type-safe globalThis casting instead of @ts-ignore directive. [#66, #67 by Martin Petrovsky]

Version 1.0.1 ​

Released on July 3, 2025.

  • Fixed React Native compatibility issue in @logtape/pretty package where top-level Node.js imports caused build failures. Replaced direct node:util imports with platform-specific utilities using conditional module loading via package.json imports map. [#63]

  • Fixed compatibility issue with Cloudflare Workers where process.on() is not available, causing configuration to fail with process.on is not a function error. LogTape now checks for process.on() availability before attempting to register exit handlers. [#64, #65 by Martin Petrovsky]

Version 1.0.0 ​

Released on June 22, 2025.

  • Added getLogLevels() function to retrieve all available log levels.

  • Added LogMethod type for better type inference of logger methods.

  • Added nonBlocking option to getConsoleSink(), getStreamSink(), getFileSink(), and getRotatingFileSink() for high-performance logging scenarios. When enabled, log records are buffered and flushed in the background, preventing blocking of the main thread.

    • Console and stream sinks accept nonBlocking?: boolean | { bufferSize?: number; flushInterval?: number } option.
    • File sinks accept nonBlocking?: boolean option.
    • Default buffer size is 100 records for console/stream sinks and background flushing for file sinks.
    • Default flush interval is 100ms for console/stream sinks.
    • Console sink returns Sink & Disposable in non-blocking mode.
    • Stream and file sinks return Sink & AsyncDisposable in non-blocking mode.
    • Buffer-full flushes are now asynchronous (non-blocking) instead of synchronous to maintain performance during high-volume logging.
    • Console and stream sinks include automatic buffer overflow protection that prevents unbounded memory growth by dropping oldest records when buffer exceeds 2x the configured size.
    • Errors during background flushing are silently ignored to prevent application disruption.

  • Added getStreamFileSink() function in @logtape/file package for high-performance file logging using Node.js PassThrough streams.

    • Added StreamFileSinkOptions interface for configuring stream-based file sink behavior.
    • Uses PassThrough streams piped to WriteStreams for optimal I/O performance with automatic backpressure management and non-blocking writes.
    • Optimized for high-volume logging scenarios with superior throughput compared to standard file sinks.
    • Simple configuration with highWaterMark (default: 16384 bytes) and optional custom formatter options.
    • Automatic stream cleanup and proper resource disposal via Disposable interface.
    • Ideal for production applications requiring high-performance file logging without complex buffering configuration.

  • Added fromAsyncSink() function to convert async sinks to regular sinks with proper async handling.

    • Added AsyncSink type: (record: LogRecord) => Promise<void>.
    • fromAsyncSink() chains async operations to ensure order preservation.
    • Errors in async sinks are caught to prevent breaking the promise chain.
    • Returns a sink with AsyncDisposable support that waits for all pending operations on disposal.

  • Added @logtape/cloudwatch-logs package for AWS CloudWatch Logs integration. [#48, #49]

    • Added getCloudWatchLogsSink() function to send logs to AWS CloudWatch Logs.
    • Added CloudWatchLogsSinkOptions interface for configuration.
    • Supports intelligent batching up to 10,000 events or 1MiB per batch.
    • Includes exponential backoff retry strategy for error handling.
    • Works with existing CloudWatch Logs clients or creates new ones automatically.
    • Supports custom AWS credentials and regions.
    • Added formatter option to support custom text formatters, including jsonLinesFormatter() for enhanced CloudWatch Logs Insights querying capabilities with dot notation support.

  • Added @logtape/windows-eventlog package for Windows Event Log integration. [#47, #50]

    • Added getWindowsEventLogSink() function to send logs to Windows Event Log.
    • Added WindowsEventLogSinkOptions interface for configuration.
    • Cross-runtime support: Works with Deno, Node.js, and Bun on Windows.
    • Uses runtime-optimized FFI implementations: Deno FFI, koffi for Node.js, and Bun FFI for maximum performance.
    • Supports all LogTape log levels with proper Event Log type mapping (Error, Warning, Information).
    • Includes structured logging support with formatted context information.
    • Added validateWindowsPlatform() function for platform validation.
    • Added WindowsPlatformError and WindowsEventLogError for proper error handling.
    • Platform-restricted installation (Windows only) for safety.
    • Includes PowerShell-based test verification for actual Event Log integration.

  • Added @logtape/pretty package for beautiful console formatting designed for local development. [#46, #51]

    • Added getPrettyFormatter() function to create visually appealing log formatters with colorful icons, smart category truncation, and perfect column alignment.
    • Added prettyFormatter constant for quick setup with sensible defaults.
    • Added PrettyFormatterOptions interface for extensive customization.
    • Features Signale-inspired design with emojis for each log level: 🔍 trace, 🐛 debug, ✨ info, ⚠️ warning, ❌ error, 💀 fatal.
    • Includes smart category truncation that preserves important context while maintaining layout (e.g., app·server…middleware).
    • Supports true color terminals with rich color schemes and dimmed text for enhanced readability.
    • Provides optional timestamp display, custom icons, color control, and flexible layout options.
    • Supports multiple text styles combination (e.g., ["bold", "underline"]) for level, category, message, and timestamp formatting.
    • Includes word wrapping feature with proper indentation alignment to maintain visual consistency for long messages.
    • Optimized for development environments with focus on visual clarity and developer experience.

  • Added @logtape/adaptor-pino package for integrating LogTape with Pino logging infrastructure. [#52]

    • Added getPinoSink() function to forward LogTape log records to Pino loggers.
    • Added PinoSinkOptions interface for configuring the adapter behavior.
    • Added CategoryOptions interface for customizing category formatting in Pino log messages.
    • Added install() function for convenient auto-configuration with custom Pino logger and configuration options.
    • Supports configurable category display with position (start/end), decorators ([], (), <>, {}, :, -, |, /, or none), and custom separators for multi-part categories.
    • Maps LogTape log levels to equivalent Pino levels.
    • Preserves LogTape's structured logging properties as Pino fields.
    • Enables seamless adoption of LogTape-enabled libraries in applications using Pino without requiring logging infrastructure changes.

  • Added @logtape/adaptor-winston package for integrating LogTape with winston logging infrastructure. [#52]

    • Added getWinstonSink() function to forward LogTape log records to winston loggers.
    • Added WinstonSinkOptions interface for configuring the adapter behavior.
    • Added CategoryOptions interface for customizing category formatting in winston log messages.
    • Added install() function for convenient auto-configuration with optional custom winston logger and configuration options.
    • Added install.ts module for automatic setup via simple import.
    • Supports configurable category display with position (start/end), decorators ([], (), <>, {}, :, -, |, /, or none), and custom separators for multi-part categories.
    • Maps LogTape log levels to equivalent winston levels with customizable level mapping.
    • Supports custom value formatters for interpolated values in log messages.
    • Preserves LogTape's structured logging properties as winston fields.
    • Enables seamless adoption of LogTape-enabled libraries in applications using winston without requiring logging infrastructure changes.

  • Fixed browser support for @logtape/otel package by removing direct node:process dependency. [#53]

    • Replaced node:process import with cross-runtime environment variable access that works in Deno, Node.js, and browsers.
    • Changed tsdown platform setting from "node" to "neutral" to enable browser compatibility.
    • The getOpenTelemetrySink() function now works in all JavaScript runtimes without throwing module resolution errors.

  • Removed the deprecated LoggerConfig.level property. Use LoggerConfig.lowestLevel instead for setting the minimum log level, or use LoggerConfig.filters for more advanced filtering.

Version 0.12.3 ​

Released on September 10, 2025.

  • The satellite packages (@logtape/file, @logtape/otel, @logtape/redaction, @logtape/sentry, and @logtape/syslog) now properly specify version compatibility constraints for their peer dependency on @logtape/logtape, ensuring consumers install compatible versions of the core package.

Version 0.12.2 ​

Released on July 6, 2025.

  • Fixed a bug where jsonLinesFormatter and the formatter returned by getJsonLinesFormatter() did not output newline characters between JSON objects, violating the JSON Lines specification that requires one JSON object per line.

Version 0.12.1 ​

Released on June 19, 2025.

  • Fixed module resolution issues in CommonJS environments and bundlers like Vite by properly configuring conditional exports for types.

    • Updated all package.json exports to use conditional types exports with separate .d.ts files for ESM imports and .d.cts files for CommonJS requires.
    • This resolves runtime errors in frameworks like SvelteKit that require proper CommonJS modules for modules imported in CommonJS contexts.

Version 0.12.0 ​

Released on June 15, 2025.

  • Added the "trace" severity level, which is lower than "debug". [#24]

  • Added Logger.warning() method which is an alias for Logger.warn(). [#44]

  • Added bufferSize and flushInterval options to FileSinkOptions for configurable buffering in file sinks.

    • getFileSink() and getRotatingFileSink() functions now accept a bufferSize option to control write buffering behavior.
    • getFileSink() and getRotatingFileSink() functions now accept a flushInterval option to control the time-based flushing of the buffer to disk.
    • When bufferSize is 0 or negative, writes are immediate without buffering.
    • When bufferSize is positive, log entries are buffered until the buffer size is exceeded, then flushed to disk.
    • Default buffer size is 8192 characters for improved performance.
    • Buffer content is automatically flushed when the sink is disposed.
    • When flushInterval is 0 or negative, the time-based flushing is disabled.
    • Default flushInterval is 5000 milliseconds (5 seconds) for periodic flushing.

  • Added @logtape/syslog package for sending log messages to syslog servers using RFC 5424 format.

    • Added getSyslogSink() function to create syslog sinks with support for both UDP and TCP protocols.
    • Supports all standard RFC 5424 facilities (kern, user, mail, daemon, local0–7, etc.) and automatic priority calculation.
    • Includes structured data support for log record properties with proper RFC 5424 escaping of special characters.
    • Cross-runtime compatibility with Deno, Node.js, and Bun.
    • Configurable connection timeouts, custom hostnames, and application names.

  • Now @logtape/otel, @logtape/sentry, and @logtape/syslog packages are released along with @logtape/logtape package. This means they share the same version number and changelog. This is to ensure that the packages are always compatible with each other and to simplify the release process.

  • Improved build and test infrastructure by migrating from dnt to tsdown for npm package bundling. [#43]

Version 0.11.1 ​

Released on July 6, 2025.

  • Fixed a bug where jsonLinesFormatter and the formatter returned by getJsonLinesFormatter() did not output newline characters between JSON objects, violating the JSON Lines specification that requires one JSON object per line.

Version 0.11.0 ​

Released on June 2, 2025.

Version 0.10.0 ​

Released on May 19, 2025.

Version 0.9.2 ​

Released on May 15, 2025.

  • Fixed a bug where importing @logtape/logtape threw a ReferenceError on Node.js or Bun when LogTape was installed from JSR (instead of npm). [#42]

Version 0.9.1 ​

Released on April 24, 2025.

  • Fixed a CORS error when using LogTape in web browser environments like Fresh islands components due to importing Node.js node:util module. [#40]

Version 0.9.0 ​

Released on March 1, 2025.

Version 0.8.2 ​

Released on February 11, 2025.

  • Fixed a bug of text formatters where they truncated string and array values in the formatted message. [#30]

Version 0.8.1 ​

Released on February 1, 2025.

  • Fixed a bug where when a child logger is configured with a lower lowestLevel than its parent logger, a log record with a severity level lower than the parent logger's lowestLevel and higher than the child logger's lowestLevel would not be filtered out by the parent logger.

Version 0.8.0 ​

Released on November 20, 2024.

Version 0.7.2 ​

Released on February 11, 2025.

  • Fixed a bug of text formatters where they truncated string and array values in the formatted message. [#30]

Version 0.7.1 ​

Released on October 30, 2024.

  • The withContext() function no more throws an error even if no contextLocalStorage is configured. Instead, it will log a warning message to the ["logtape", "meta"] logger.

Version 0.7.0 ​

Released on October 29, 2024.

Version 0.6.5 ​

Released on February 11, 2025.

  • Fixed a bug of text formatters where they truncated string and array values in the formatted message. [#30]

Version 0.6.4 ​

Released on October 28, 2024.

  • Fixed a build warning due to importing node:fs and node:util modules on Next.js' client rendering. [#19]
  • Made it to work on Deno 2.0.0 or higher.

Version 0.6.3 ​

Released on October 3, 2024.

  • Fixed a build error due to importing node:fs and node:util modules on Next.js' client rendering.

Version 0.6.2 ​

Released on September 24, 2024.

  • Fixed a build warning due to importing node:util module on Next.js. [#11]

Version 0.6.1 ​

Released on September 24, 2024.

  • Fixed a build error due to importing node:util module on Vite. [#18]

Version 0.6.0 ​

Released on September 24, 2024.

Version 0.5.4 ​

Released on September 24, 2024.

  • Fixed a build warning due to importing node:util module on Next.js. [#11]

Version 0.5.3 ​

Released on September 24, 2024.

  • Fixed a build error due to importing node:util module on Vite. [#18]

Version 0.5.2 ​

Released on September 23, 2024.

  • Fixed a build error due to top-level await on Vite. [#14]

Version 0.5.1 ​

Released on September 10, 2024.

  • Fixed a bug of defaultTextFormatter() function where it rendered embedded values in the message as JSON instead of util.inspect() on Node.js and Bun.

  • Fixed a bug of ansiColorFormatter() function where it failed to colorize embedded values in the message on Node.js and Bun.

Version 0.5.0 ​

Released on August 29, 2024.

  • LogTape now provides contexts for loggers. [#7, #8]

  • The console sink now can take a TextFormatter besides a ConsoleFormatter for formatting log records.

  • Added ansiColorFormatter() function.

  • configure() function's filters option became optional.

    • The type of Config.filters became Record<string, FilterLike> | undefined (was Record<string, FilterLike>).

Version 0.4.3 ​

Released on August 22, 2024.

  • Fixed a bug where getRotatingFileSink() function had failed to create a new log file when there's no log file to rotate yet. [#9]

Version 0.4.2 ​

Released on July 15, 2024.

  • LogTape now works well on edge functions. [#5]

    • The npm version of LogTape no more depends on node:stream/web module.
    • LogTape now works well with JavaScript runtimes that do not support node:fs module.
    • LogTape now works well with JavaScript runtimes that do not support WeakRef class.
    • Got rid of eval() from LogTape.

Version 0.4.1 ​

Released on July 2, 2024.

  • Fixed a bug where LogTape failed to load under Node.js when incorporated in a project from JSR. [#3, #4 by Kitson Kelly]

Version 0.4.0 ​

Released on May 7, 2024.

  • Curly braces can now be escaped with double curly braces. [#1, #2 by Diyar Oktay]

Version 0.3.1 ​

Released on May 7, 2024.

  • Fixed a bug where two or more versions of LogTape were imported in the same runtime, the Logger instances would not be shared between them. This was caused by the Logger instances being stored in a module-level variable.

Version 0.3.0 ​

Released on April 22, 2024.

Version 0.2.3 ​

Released on May 7, 2024.

  • Fixed a bug where two or more versions of LogTape were imported in the same runtime, the Logger instances would not be shared between them. This was caused by the Logger instances being stored in a module-level variable.

Version 0.2.2 ​

Released on April 21, 2024.

  • Fixed a bug where the configured sinks and filters were reset after some inactivity. This was caused by garbage collection of the Logger instances. The Logger instances are now kept alive by an internal set of strong references until explicitly reset() is called.

Version 0.2.1 ​

Released on April 20, 2024.

Version 0.2.0 ​

Released on April 20, 2024.

  • Sinks now can be asynchronously disposed of. This is useful for sinks that need to flush their buffers before being closed.

    • Added dispose() function.
    • The return type of configure() function became Promise<void> (was void).
    • The return type of reset() function became Promise<void> (was void).
    • Configured sinks that implement AsyncDisposable are now disposed of asynchronously when the configuration is reset or the program exits.

  • The return type of getStreamSink() function became Sink & AsyncDisposable (was Sink & Disposable).

  • Added getRotatingFileSink() function.

Version 0.1.2 ​

Released on May 7, 2024.

  • Fixed a bug where two or more versions of LogTape were imported in the same runtime, the Logger instances would not be shared between them. This was caused by the Logger instances being stored in a module-level variable.

Version 0.1.1 ​

Released on April 21, 2024.

  • Fixed a bug where the configured sinks and filters were reset after some inactivity. This was caused by garbage collection of the Logger instances. The Logger instances are now kept alive by an internal set of strong references until explicitly reset() is called.

Version 0.1.0 ​

Initial release. Released on April 19, 2024.