1
  2/**
  3 * This is the web browser implementation of `debug()`.
  4 *
  5 * Expose `debug()` as the module.
  6 */
  7
  8exports = module.exports = require('./debug');
  9exports.log = log;
 10exports.formatArgs = formatArgs;
 11exports.save = save;
 12exports.load = load;
 13exports.useColors = useColors;
 14exports.storage = 'undefined' != typeof chrome
 15               && 'undefined' != typeof chrome.storage
 16                  ? chrome.storage.local
 17                  : localstorage();
 18
 19/**
 20 * Colors.
 21 */
 22
 23exports.colors = [
 24  'lightseagreen',
 25  'forestgreen',
 26  'goldenrod',
 27  'dodgerblue',
 28  'darkorchid',
 29  'crimson'
 30];
 31
 32/**
 33 * Currently only WebKit-based Web Inspectors, Firefox >= v31,
 34 * and the Firebug extension (any Firefox version) are known
 35 * to support "%c" CSS customizations.
 36 *
 37 * TODO: add a `localStorage` variable to explicitly enable/disable colors
 38 */
 39
 40function useColors() {
 41  // is webkit? http://stackoverflow.com/a/16459606/376773
 42  return ('WebkitAppearance' in document.documentElement.style) ||
 43    // is firebug? http://stackoverflow.com/a/398120/376773
 44    (window.console && (console.firebug || (console.exception && console.table))) ||
 45    // is firefox >= v31?
 46    // https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
 47    (navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/) && parseInt(RegExp.$1, 10) >= 31);
 48}
 49
 50/**
 51 * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
 52 */
 53
 54exports.formatters.j = function(v) {
 55  return JSON.stringify(v);
 56};
 57
 58
 59/**
 60 * Colorize log arguments if enabled.
 61 *
 62 * @api public
 63 */
 64
 65function formatArgs() {
 66  var args = arguments;
 67  var useColors = this.useColors;
 68
 69  args[0] = (useColors ? '%c' : '')
 70    + this.namespace
 71    + (useColors ? ' %c' : ' ')
 72    + args[0]
 73    + (useColors ? '%c ' : ' ')
 74    + '+' + exports.humanize(this.diff);
 75
 76  if (!useColors) return args;
 77
 78  var c = 'color: ' + this.color;
 79  args = [args[0], c, 'color: inherit'].concat(Array.prototype.slice.call(args, 1));
 80
 81  // the final "%c" is somewhat tricky, because there could be other
 82  // arguments passed either before or after the %c, so we need to
 83  // figure out the correct index to insert the CSS into
 84  var index = 0;
 85  var lastC = 0;
 86  args[0].replace(/%[a-z%]/g, function(match) {
 87    if ('%%' === match) return;
 88    index++;
 89    if ('%c' === match) {
 90      // we only are interested in the *last* %c
 91      // (the user may have provided their own)
 92      lastC = index;
 93    }
 94  });
 95
 96  args.splice(lastC, 0, c);
 97  return args;
 98}
 99
100/**
101 * Invokes `console.log()` when available.
102 * No-op when `console.log` is not a "function".
103 *
104 * @api public
105 */
106
107function log() {
108  // this hackery is required for IE8/9, where
109  // the `console.log` function doesn't have 'apply'
110  return 'object' === typeof console
111    && console.log
112    && Function.prototype.apply.call(console.log, console, arguments);
113}
114
115/**
116 * Save `namespaces`.
117 *
118 * @param {String} namespaces
119 * @api private
120 */
121
122function save(namespaces) {
123  try {
124    if (null == namespaces) {
125      exports.storage.removeItem('debug');
126    } else {
127      exports.storage.debug = namespaces;
128    }
129  } catch(e) {}
130}
131
132/**
133 * Load `namespaces`.
134 *
135 * @return {String} returns the previously persisted debug modes
136 * @api private
137 */
138
139function load() {
140  var r;
141  try {
142    r = exports.storage.debug;
143  } catch(e) {}
144  return r;
145}
146
147/**
148 * Enable namespaces listed in `localStorage.debug` initially.
149 */
150
151exports.enable(load());
152
153/**
154 * Localstorage attempts to return the localstorage.
155 *
156 * This is necessary because safari throws
157 * when a user disables cookies/localstorage
158 * and you attempt to access it.
159 *
160 * @return {LocalStorage}
161 * @api private
162 */
163
164function localstorage(){
165  try {
166    return window.localStorage;
167  } catch (e) {}
168}