@probe.gl/log/src/loggers/log-utils.ts

JavaScript debug logging for browser and Node

// probe.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors

import assert from '../utils/assert';

/**
 * Get logLevel from first argument:
 * - log(logLevel, message, args) => logLevel
 * - log(message, args) => 0
 * - log({logLevel, ...}, message, args) => logLevel
 * - log({logLevel, message, args}) => logLevel
 */
export function normalizeLogLevel(logLevel: unknown): number {
  if (!logLevel) {
    return 0;
  }
  let resolvedLevel;

  switch (typeof logLevel) {
    case 'number':
      resolvedLevel = logLevel;
      break;

    case 'object':
      // Backward compatibility
      // TODO - deprecate `priority`
      // @ts-expect-error
      resolvedLevel = logLevel.logLevel || logLevel.priority || 0;
      break;

    default:
      return 0;
  }
  // 'log level must be a number'
  assert(Number.isFinite(resolvedLevel) && resolvedLevel >= 0);

  return resolvedLevel;
}

/**
 * "Normalizes" the various argument patterns into an object with known types
 * - log(logLevel, message, args) => {logLevel, message, args}
 * - log(message, args) => {logLevel: 0, message, args}
 * - log({logLevel, ...}, message, args) => {logLevel, message, args}
 * - log({logLevel, message, args}) => {logLevel, message, args}
 */
export function normalizeArguments(opts: {
  logLevel;
  message;
  collapsed?: boolean;
  args?: IArguments | any[] | undefined;
  opts?;
}): NormalizedArguments {
  const {logLevel, message} = opts;
  opts.logLevel = normalizeLogLevel(logLevel);

  // We use `arguments` instead of rest parameters (...args) because IE
  // does not support the syntax. Rest parameters is transpiled to code with
  // perf impact. Doing it here instead avoids constructing args when logging is
  // disabled.
  // TODO - remove when/if IE support is dropped
  const args: any[] = opts.args ? Array.from(opts.args) : [];
  // args should only contain arguments that appear after `message`
  // eslint-disable-next-line no-empty
  while (args.length && args.shift() !== message) {}

  switch (typeof logLevel) {
    case 'string':
    case 'function':
      if (message !== undefined) {
        args.unshift(message);
      }
      opts.message = logLevel;
      break;

    case 'object':
      Object.assign(opts, logLevel);
      break;

    default:
  }

  // Resolve functions into strings by calling them
  if (typeof opts.message === 'function') {
    opts.message = opts.message();
  }
  const messageType = typeof opts.message;
  // 'log message must be a string' or object
  assert(messageType === 'string' || messageType === 'object');

  // original opts + normalized opts + opts arg + fixed up message
  return Object.assign(opts, {args}, opts.opts);
}
export type NormalizedArguments = {
  logLevel: number;
  message: any;
  args: any[];
  tag?: unknown;
  method?: Function;
  once?: boolean;
  total?: number;
  delta?: number;
  [key: string]: any;
};