colorize.js

'use strict';

const colors = require('colors/safe');
const { LEVEL, MESSAGE } = require('triple-beam');

//
// Fix colors not appearing in non-tty environments
//
colors.enabled = true;

/**
 * @property {RegExp} hasSpace
 * Simple regex to check for presence of spaces.
 */
const hasSpace = /\s+/;

/*
 * Colorizer format. Wraps the `level` and/or `message` properties
 * of the `info` objects with ANSI color codes based on a few options.
 */
class Colorizer {
  constructor(opts = {}) {
    if (opts.colors) {
      this.addColors(opts.colors);
    }

    this.options = opts;
  }

  /*
   * Adds the colors Object to the set of allColors
   * known by the Colorizer
   *
   * @param {Object} colors Set of color mappings to add.
   */
  static addColors(clrs) {
    const nextColors = Object.keys(clrs).reduce((acc, level) => {
      acc[level] = hasSpace.test(clrs[level])
        ? clrs[level].split(hasSpace)
        : clrs[level];

      return acc;
    }, {});

    Colorizer.allColors = Object.assign({}, Colorizer.allColors || {}, nextColors);
    return Colorizer.allColors;
  }

  /*
   * Adds the colors Object to the set of allColors
   * known by the Colorizer
   *
   * @param {Object} colors Set of color mappings to add.
   */
  addColors(clrs) {
    return Colorizer.addColors(clrs);
  }

  /*
   * function colorize (lookup, level, message)
   * Performs multi-step colorization using colors/safe
   */
  colorize(lookup, level, message) {
    if (typeof message === 'undefined') {
      message = level;
    }

    //
    // If the color for the level is just a string
    // then attempt to colorize the message with it.
    //
    if (!Array.isArray(Colorizer.allColors[lookup])) {
      return colors[Colorizer.allColors[lookup]](message);
    }

    //
    // If it is an Array then iterate over that Array, applying
    // the colors function for each item.
    //
    for (let i = 0, len = Colorizer.allColors[lookup].length; i < len; i++) {
      message = colors[Colorizer.allColors[lookup][i]](message);
    }

    return message;
  }

  /*
   * function transform (info, opts)
   * Attempts to colorize the { level, message } of the given
   * `logform` info object.
   */
  transform(info, opts) {
    if (opts.all && typeof info[MESSAGE] === 'string') {
      info[MESSAGE] = this.colorize(info[LEVEL], info.level, info[MESSAGE]);
    }

    if (opts.level || opts.all || !opts.message) {
      info.level = this.colorize(info[LEVEL], info.level);
    }

    if (opts.all || opts.message) {
      info.message = this.colorize(info[LEVEL], info.level, info.message);
    }

    return info;
  }
}

/*
 * function colorize (info)
 * Returns a new instance of the colorize Format that applies
 * level colors to `info` objects. This was previously exposed
 * as { colorize: true } to transports in `winston < 3.0.0`.
 */
module.exports = opts => new Colorizer(opts);

//
// Attach the Colorizer for registration purposes
//
module.exports.Colorizer
  = module.exports.Format
  = Colorizer;