added unit testing, and started implementing unit tests...phew

node_modules/logform/pad-levels.js

@@ -0,0 +1,83 @@
+/* eslint no-unused-vars: 0 */
+'use strict';
+
+const { configs, LEVEL, MESSAGE } = require('triple-beam');
+
+class Padder {
+  constructor(opts = { levels: configs.npm.levels }) {
+    this.paddings = Padder.paddingForLevels(opts.levels, opts.filler);
+    this.options = opts;
+  }
+
+  /**
+   * Returns the maximum length of keys in the specified `levels` Object.
+   * @param  {Object} levels Set of all levels to calculate longest level against.
+   * @returns {Number} Maximum length of the longest level string.
+   */
+  static getLongestLevel(levels) {
+    const lvls = Object.keys(levels).map(level => level.length);
+    return Math.max(...lvls);
+  }
+
+  /**
+   * Returns the padding for the specified `level` assuming that the
+   * maximum length of all levels it's associated with is `maxLength`.
+   * @param  {String} level Level to calculate padding for.
+   * @param  {String} filler Repeatable text to use for padding.
+   * @param  {Number} maxLength Length of the longest level
+   * @returns {String} Padding string for the `level`
+   */
+  static paddingForLevel(level, filler, maxLength) {
+    const targetLen = maxLength + 1 - level.length;
+    const rep = Math.floor(targetLen / filler.length);
+    const padding = `${filler}${filler.repeat(rep)}`;
+    return padding.slice(0, targetLen);
+  }
+
+  /**
+   * Returns an object with the string paddings for the given `levels`
+   * using the specified `filler`.
+   * @param  {Object} levels Set of all levels to calculate padding for.
+   * @param  {String} filler Repeatable text to use for padding.
+   * @returns {Object} Mapping of level to desired padding.
+   */
+  static paddingForLevels(levels, filler = ' ') {
+    const maxLength = Padder.getLongestLevel(levels);
+    return Object.keys(levels).reduce((acc, level) => {
+      acc[level] = Padder.paddingForLevel(level, filler, maxLength);
+      return acc;
+    }, {});
+  }
+
+  /**
+   * Prepends the padding onto the `message` based on the `LEVEL` of
+   * the `info`. This is based on the behavior of `winston@2` which also
+   * prepended the level onto the message.
+   *
+   * See: https://github.com/winstonjs/winston/blob/2.x/lib/winston/logger.js#L198-L201
+   *
+   * @param  {Info} info Logform info object
+   * @param  {Object} opts Options passed along to this instance.
+   * @returns {Info} Modified logform info object.
+   */
+  transform(info, opts) {
+    info.message = `${this.paddings[info[LEVEL]]}${info.message}`;
+    if (info[MESSAGE]) {
+      info[MESSAGE] = `${this.paddings[info[LEVEL]]}${info[MESSAGE]}`;
+    }
+
+    return info;
+  }
+}
+
+/*
+ * function padLevels (info)
+ * Returns a new instance of the padLevels Format which pads
+ * levels to be the same length. This was previously exposed as
+ * { padLevels: true } to transports in `winston < 3.0.0`.
+ */
+module.exports = opts => new Padder(opts);
+
+module.exports.Padder
+  = module.exports.Format
+  = Padder;