A filter transform which uses a predicate(_:LogEntry) function to process and selectively discard entries.

Transform a LogEntry into a human-readable string (ie, for console display).

• input: LogEntry
• output: string
• options?: ... ToDO ...

Logger. This is what we write to.

Semi-structured data accessible to consumers of LogEntry via getData(), getProp...(), etc.

Default log level properties for the built-in Humane transform.

Default log levels; adds 'trace' to the traditional RFC3164 list.

• ref: http://www.faqs.org/rfcs/rfc3164.html@@https://archive.is/Pu3Eu

Return the value of the environment variable varName (or undefined if non-existent or not-allowed access).

• will not panic
• will not prompt for permission if options.guard is true

The log entry that Logger creates and forwards to its chained transforms and writers.

Configuration for the Logger

Transform function type; describes a simple generic function to perform data transformation.

Transform function type; describes a simple generic function to perform data transformation. The function takes a context object and an array of input type (I) as rest parameters and which returns an output type (O), undefined, or a promise of either.

A type defining a function which takes an input string and outputs the string with formatting (eg, bold, red, italics, etc) applied to it.