debug.js 2.4 KB

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  1. /**
  2. * Expose `debug()` as the module.
  3. */
  4. module.exports = debug;
  5. /**
  6. * Create a debugger with the given `name`.
  7. *
  8. * @param {String} name
  9. * @return {Type}
  10. * @api public
  11. */
  12. function debug(name) {
  13. if (!debug.enabled(name)) return function(){};
  14. return function(fmt){
  15. fmt = coerce(fmt);
  16. var curr = new Date;
  17. var ms = curr - (debug[name] || curr);
  18. debug[name] = curr;
  19. fmt = name
  20. + ' '
  21. + fmt
  22. + ' +' + debug.humanize(ms);
  23. // This hackery is required for IE8
  24. // where `console.log` doesn't have 'apply'
  25. window.console
  26. && console.log
  27. && Function.prototype.apply.call(console.log, console, arguments);
  28. }
  29. }
  30. /**
  31. * The currently active debug mode names.
  32. */
  33. debug.names = [];
  34. debug.skips = [];
  35. /**
  36. * Enables a debug mode by name. This can include modes
  37. * separated by a colon and wildcards.
  38. *
  39. * @param {String} name
  40. * @api public
  41. */
  42. debug.enable = function(name) {
  43. try {
  44. localStorage.debug = name;
  45. } catch(e){}
  46. var split = (name || '').split(/[\s,]+/)
  47. , len = split.length;
  48. for (var i = 0; i < len; i++) {
  49. name = split[i].replace('*', '.*?');
  50. if (name[0] === '-') {
  51. debug.skips.push(new RegExp('^' + name.substr(1) + '$'));
  52. }
  53. else {
  54. debug.names.push(new RegExp('^' + name + '$'));
  55. }
  56. }
  57. };
  58. /**
  59. * Disable debug output.
  60. *
  61. * @api public
  62. */
  63. debug.disable = function(){
  64. debug.enable('');
  65. };
  66. /**
  67. * Humanize the given `ms`.
  68. *
  69. * @param {Number} m
  70. * @return {String}
  71. * @api private
  72. */
  73. debug.humanize = function(ms) {
  74. var sec = 1000
  75. , min = 60 * 1000
  76. , hour = 60 * min;
  77. if (ms >= hour) return (ms / hour).toFixed(1) + 'h';
  78. if (ms >= min) return (ms / min).toFixed(1) + 'm';
  79. if (ms >= sec) return (ms / sec | 0) + 's';
  80. return ms + 'ms';
  81. };
  82. /**
  83. * Returns true if the given mode name is enabled, false otherwise.
  84. *
  85. * @param {String} name
  86. * @return {Boolean}
  87. * @api public
  88. */
  89. debug.enabled = function(name) {
  90. for (var i = 0, len = debug.skips.length; i < len; i++) {
  91. if (debug.skips[i].test(name)) {
  92. return false;
  93. }
  94. }
  95. for (var i = 0, len = debug.names.length; i < len; i++) {
  96. if (debug.names[i].test(name)) {
  97. return true;
  98. }
  99. }
  100. return false;
  101. };
  102. /**
  103. * Coerce `val`.
  104. */
  105. function coerce(val) {
  106. if (val instanceof Error) return val.stack || val.message;
  107. return val;
  108. }
  109. // persist
  110. try {
  111. if (window.localStorage) debug.enable(localStorage.debug);
  112. } catch(e){}