v1.0.0 - 2026-09-17

Headlines

• Added dual esm/cjs output to support ESM consumers.

Changed

• Log.addTransport now returns a TransportAddResult object ({ok, errorCode?, errors?}) instead of a boolean, and never throws. Transport construction failures are reported with errorCode: 'transport_init_failed' and the thrown error in errors.
• Transport ctor now throws when level is not a valid log level instead of silently defaulting to Levels.NONE.

Fixed

• startingGroups now runs at the end of the Log ctor and no longer throws when provided.
• make('a.b') no longer creates a group keyed root.a.b whose parent is root instead of root.a, which collided with root.make('a').make('b'). Group ids and parents now always match the full hierarchy.
• Ids that are whitespace-only or contain an empty segment ('a..b', '.a') now return null instead of creating a group with a malformed id.

Added

• Log.make(id, options?) replaces makeLog as the way to get or create a child log group. makeLog remains as a deprecated alias that calls make, so existing call sites keep working.
• A dotted id walks the hierarchy one segment at a time, so root.make('a.b') returns the same log as root.make('a').make('b') and creates missing intermediate groups.
• LevelKey string union ('none' | 'error' | 'warn' | 'info' | 'debug' | 'trace' | 'all' | 'all_custom' | 'all_extended') is accepted anywhere a level bitmask is: Log level methods, Log.log, LogLevel, Transport, and the globalLevel/level options. Levels are still stored and compared as bitmasks internally.
• Level arguments also accept an array mixing keys and bitmasks. enableLevel/disableLevel style methods resolve each item to its bitmask and apply it in order, one at a time. set, log, and constructors combine the array with bitwise OR into a single mask.
• LevelKeys map from key to bitmask, LevelInput type (number | LevelKey), checkLevelKey type guard, and levelMask helper that resolves a key, bitmask, or array to a bitmask, or null when any input is invalid.