Class: Logger

Logger(name, …args)

Standardized logger for consistent, prefixed, and optionally colorized logging throughout the application. Supports multiple log levels, custom prefixes, telemetry, and error handling utilities.

Constructor

new Logger(name, …args)

Constructs a Logger instance with the given name and optional additional prefixes.
Parameters:
Name Type Attributes Description
name string The main name or component for the logger prefix.
args string | boolean | null | undefined <repeatable>
 Additional prefix arguments.
Properties:
Name Type Description
logPrefix string The formatted prefix for all log messages from this logger.
prefixes Array.<string> The list of prefix strings used to build the logPrefix.

Members

debug

console.debug() with the logger's prefix.

deep

Calls 'debug()' to log but only if FEDIALGO_DEEP_DEBUG env var is set.

info

console.info() with the logger's prefix.

log

console.log() with the logger's prefix.

trace

Calls 'debug()' to log but only if FEDIALGO_DEBUG env var is set.

warn

Call console.warn() with the logger's prefix. Checks for Error objs in args in the same way as `error()`.

warnWithoutTrace

Logs a warning message with a warn colored prefix (not a real warning level).

Methods

error(msg, …args) → {string}

Logs an error message or Error object to the console with the logger's prefix. Checks whether any element of 'args' is an instance of Error for special handling.
Parameters:
Name Type Attributes Description
msg string | Error The error message or Error object.
args any <repeatable>
 Additional arguments to log.
Returns:
The error message string.
Type
string

line(msg) → {string}

Concatenates the logger's prefix and the given message.
Parameters:
Name Type Description
msg string | undefined The message to prefix.
Returns:
The prefixed log line.
Type
string

logAndThrowError(msg, …args)

Logs an error message and throws an Error with the stringified arguments and message.
Parameters:
Name Type Attributes Description
msg string The error message.
args any <repeatable>
 Additional arguments to include in the error.
Throws:
A new Error with the formatted message, optionally including the first Error argument.
Type
Error

logArrayReduction(before, after, objType, reasonopt)

Logs the reduction in size of an array (e.g., after filtering or deduplication).
Parameters:
Name Type Attributes Description
before Array.<T> The array before reduction.
after Array.<T> The array after reduction.
objType string The type of object in the array.
reason string <optional>
 Optional reason for reduction.

logSortedDict(msg, dict)

Logs a sorted dictionary of string-number pairs.
Parameters:
Name Type Description
msg string The message to log before the dictionary.
dict StringNumberDict The dictionary to log.

logTelemetry(msg, startedAt, …args)

Logs a message with the elapsed time since startedAt, optionally with additional labels/args.
Parameters:
Name Type Attributes Description
msg string The message to log.
startedAt Date The start time to compute elapsed time.
args any <repeatable>
 Additional arguments or labels.

tagWithRandomString()

Adds a random string to the logger's prefix (useful for distinguishing logs in concurrent contexts).

tempLogger(arg1, …args) → {module:helpers/logger~Logger}

Returns a new Logger with additional prefix arguments appended to this.prefixes.
Parameters:
Name Type Attributes Description
arg1 string The additional prefix.
args LoggerArg <repeatable>
 More prefix arguments.
Returns:
A new Logger instance with the extended prefix.
Type
module:helpers/logger~Logger

(static) logBuilder(name, …prefixes) → {function}

Returns a function that builds Logger objects with the starting prefixes.
Parameters:
Name Type Attributes Description
name string The main name for the logger.
prefixes LoggerArg <repeatable>
 Additional prefixes.
Returns:
A function that creates Logger instances with the given prefixes.
Type
function

(static) withParenthesizedName(name, parenthesized, …args) → {module:helpers/logger~Logger}

Alternate constructor; makes the first two arguments into a parenthesized bracketed string. e.g. the prefix will be [name (parenthesized)].
Parameters:
Name Type Attributes Description
name string The main name for the logger.
parenthesized string The value to parenthesize in the prefix.
args string <repeatable>
 Additional prefix arguments.
Returns:
A new Logger instance with the custom prefix.
Type
module:helpers/logger~Logger