debugger for frontend

debug.js

define(function(require, exports, module) {
  // Debug:
  //   print:
  //     Debug(name, [withTrace])(obj, [obj, ...])
  //   enable:
  //     Debug.enable()
  //   disable:
  //     Debug.disable()
  //     Debug.disable(name, [name, ...])
  //   only:
  //     Debug.only(name, [name, ...])
  var Debug = (function () {
    var COLOR = {
      prefix: '#f47920',
      timestamp: '#FE5000'
    };
    var STORE = 'debug';
    var NOOP = function () {};
    var setting = {
      enabled: false,
      disabled: [],
      only: []
    };
    var color, store, timestamp, Debug;
    var console, log, trace;
    if (!window.console || !window.console.log || !window.console.trace) {
      Debug = function () {
        return NOOP;
      };
      Debug.enable = Debug.only = Debug.disable = NOOP;
      return Debug;
    }
    console = window.console;
    log = console.log;
    trace = console.trace;

    color = function (hex) {
      return 'color: ' + hex + ';';
    };

    store = {
      read: function () {
        try {
          if (window.localStorage) {
            setting.enabled = JSON.parse(localStorage.getItem(STORE + ':setting')).enabled;
          }
        } catch (e) {}
      },
      update: function () {
        try {
          if (window.localStorage) {
            localStorage.setItem(STORE + ':setting', JSON.stringify(setting));
          }
        } catch (e) {}
      }
    };

    timestamp = (function () {
      var second = 1000;
      var minute = second * 60;
      var hour = minute * 60;
      var cache = {};
      var get = function (ns) {
        var previous;
        if (typeof cache[ns] === 'undefined') {
          cache[ns] = +new Date();
          return 0;
        }
        previous = cache[ns];
        cache[ns] = +new Date();
        return cache[ns] - previous;
      };
      return function (ns) {
        return '+' + get(ns) + 'ms';
      };
    })();

    Debug = function (ns, withTrace) {
      return function () {
        var args, first;
        if (!setting.enabled) {
          return;
        }
        if (setting.only.length > 0) {
          if (setting.only.indexOf(ns) === -1) {
            return;
          }
        } else {
          if (setting.disabled.indexOf(ns) > -1) {
            return;
          }
        }
        args = Array.prototype.slice.call(arguments);
        first = args[0];
        try {
          log.apply(console, ['%c[debug - ' + ns + ' %c' + timestamp(ns) + '%c]%c']
            .concat([color(COLOR.prefix), color(COLOR.timestamp), color(COLOR.prefix), ''])
            .concat(args)
            );
        } catch (e) {
          log.apply(console, ['[debug - ' + ns + ' ' + timestamp(ns) + ']'].concat(args));
        }
        if (withTrace) {
          trace.apply(console);
        }
      };
    };
    Debug.enable = function () {
      setting.enabled = true;
      store.update();
    };
    Debug.only = function () {
      var args = Array.prototype.slice.call(arguments);
      var i, length;
      for (i = 0, len = args.length; i < len; i++) {
        if (setting.only.indexOf(args[i]) === -1) {
          setting.only.push(args[i]);
        }
      }
    };
    Debug.disable = function () {
      var args = Array.prototype.slice.call(arguments);
      var i, len;
      if (args.length === 0) {
        setting.enabled = false;
        store.update();
      }
      for (i = 0, len = args.length; i < len; i++) {
        if (setting.disabled.indexOf(args[i]) === -1) {
          setting.disabled.push(args[i]);
        }
      }
    };

    store.read();

    return Debug;
  })();

  Debug('yelo', true)('^ ^');

  module.exports = window.Debug = Debug;

});