index.js

/**
 * Module dependencies.
 */

var map = require('array-map');
var indexOf = require('indexof');
var isArray = require('isarray');
var forEach = require('foreach');
var reduce = require('array-reduce');
var getObjectKeys = require('object-keys');
var JSON = require('json3');

/**
 * Make sure `Object.keys` work for `undefined`
 * values that are still there, like `document.all`.
 * http://lists.w3.org/Archives/Public/public-html/2009Jun/0546.html
 *
 * @api private
 */

function objectKeys(val){
  if (Object.keys) return Object.keys(val);
  return getObjectKeys(val);
}

/**
 * Module exports.
 */

module.exports = inspect;

/**
 * Echos the value of a value. Trys to print the value out
 * in the best way possible given the different types.
 *
 * @param {Object} obj The object to print out.
 * @param {Object} opts Optional options object that alters the output.
 * @license MIT (© Joyent)
 */
/* legacy: obj, showHidden, depth, colors*/

function inspect(obj, opts) {
  // default options
  var ctx = {
    seen: [],
    stylize: stylizeNoColor
  };
  // legacy...
  if (arguments.length >= 3) ctx.depth = arguments[2];
  if (arguments.length >= 4) ctx.colors = arguments[3];
  if (isBoolean(opts)) {
    // legacy...
    ctx.showHidden = opts;
  } else if (opts) {
    // got an "options" object
    _extend(ctx, opts);
  }
  // set default options
  if (isUndefined(ctx.showHidden)) ctx.showHidden = false;
  if (isUndefined(ctx.depth)) ctx.depth = 2;
  if (isUndefined(ctx.colors)) ctx.colors = false;
  if (isUndefined(ctx.customInspect)) ctx.customInspect = true;
  if (ctx.colors) ctx.stylize = stylizeWithColor;
  return formatValue(ctx, obj, ctx.depth);
}

// http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
inspect.colors = {
  'bold' : [1, 22],
  'italic' : [3, 23],
  'underline' : [4, 24],
  'inverse' : [7, 27],
  'white' : [37, 39],
  'grey' : [90, 39],
  'black' : [30, 39],
  'blue' : [34, 39],
  'cyan' : [36, 39],
  'green' : [32, 39],
  'magenta' : [35, 39],
  'red' : [31, 39],
  'yellow' : [33, 39]
};

// Don't use 'blue' not visible on cmd.exe
inspect.styles = {
  'special': 'cyan',
  'number': 'yellow',
  'boolean': 'yellow',
  'undefined': 'grey',
  'null': 'bold',
  'string': 'green',
  'date': 'magenta',
  // "name": intentionally not styling
  'regexp': 'red'
};

function stylizeNoColor(str, styleType) {
  return str;
}

function isBoolean(arg) {
  return typeof arg === 'boolean';
}

function isUndefined(arg) {
  return arg === void 0;
}

function stylizeWithColor(str, styleType) {
  var style = inspect.styles[styleType];

  if (style) {
    return '\u001b[' + inspect.colors[style][0] + 'm' + str +
           '\u001b[' + inspect.colors[style][1] + 'm';
  } else {
    return str;
  }
}

function isFunction(arg) {
  return typeof arg === 'function';
}

function isString(arg) {
  return typeof arg === 'string';
}

function isNumber(arg) {
  return typeof arg === 'number';
}

function isNull(arg) {
  return arg === null;
}

function hasOwn(obj, prop) {
  return Object.prototype.hasOwnProperty.call(obj, prop);
}

function isRegExp(re) {
  return isObject(re) && objectToString(re) === '[object RegExp]';
}

function isObject(arg) {
  return typeof arg === 'object' && arg !== null;
}

function isError(e) {
  return isObject(e) &&
      (objectToString(e) === '[object Error]' || e instanceof Error);
}

function isDate(d) {
  return isObject(d) && objectToString(d) === '[object Date]';
}

function objectToString(o) {
  return Object.prototype.toString.call(o);
}

function arrayToHash(array) {
  var hash = {};

  forEach(array, function(val, idx) {
    hash[val] = true;
  });

  return hash;
}

function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = [];
  for (var i = 0, l = value.length; i < l; ++i) {
    if (hasOwn(value, String(i))) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          String(i), true));
    } else {
      output.push('');
    }
  }
  forEach(keys, function(key) {
    if (!key.match(/^\d+$/)) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          key, true));
    }
  });
  return output;
}

function formatError(value) {
  return '[' + Error.prototype.toString.call(value) + ']';
}

function formatValue(ctx, value, recurseTimes) {
  // Provide a hook for user-specified inspect functions.
  // Check that value is an object with an inspect function on it
  if (ctx.customInspect &&
      value &&
      isFunction(value.inspect) &&
      // Filter out the util module, it's inspect function is special
      value.inspect !== inspect &&
      // Also filter out any prototype objects using the circular check.
      !(value.constructor && value.constructor.prototype === value)) {
    var ret = value.inspect(recurseTimes, ctx);
    if (!isString(ret)) {
      ret = formatValue(ctx, ret, recurseTimes);
    }
    return ret;
  }

  // Primitive types cannot have properties
  var primitive = formatPrimitive(ctx, value);
  if (primitive) {
    return primitive;
  }

  // Look up the keys of the object.
  var keys = objectKeys(value);
  var visibleKeys = arrayToHash(keys);

  try {
    if (ctx.showHidden && Object.getOwnPropertyNames) {
      keys = Object.getOwnPropertyNames(value);
    }
  } catch (e) {
    // ignore
  }

  // IE doesn't make error fields non-enumerable
  // http://msdn.microsoft.com/en-us/library/ie/dww52sbt(v=vs.94).aspx
  if (isError(value)
      && (indexOf(keys, 'message') >= 0 || indexOf(keys, 'description') >= 0)) {
    return formatError(value);
  }

  // Some type of object without properties can be shortcutted.
  if (keys.length === 0) {
    if (isFunction(value)) {
      var name = value.name ? ': ' + value.name : '';
      return ctx.stylize('[Function' + name + ']', 'special');
    }
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    }
    if (isDate(value)) {
      return ctx.stylize(Date.prototype.toString.call(value), 'date');
    }
    if (isError(value)) {
      return formatError(value);
    }
  }

  var base = '', array = false, braces = ['{', '}'];

  // Make Array say that they are Array
  if (isArray(value)) {
    array = true;
    braces = ['[', ']'];
  }

  // Make functions say that they are functions
  if (isFunction(value)) {
    var n = value.name ? ': ' + value.name : '';
    base = ' [Function' + n + ']';
  }

  // Make RegExps say that they are RegExps
  if (isRegExp(value)) {
    base = ' ' + RegExp.prototype.toString.call(value);
  }

  // Make dates with properties first say the date
  if (isDate(value)) {
    base = ' ' + Date.prototype.toUTCString.call(value);
  }

  // Make error with message first say the error
  if (isError(value)) {
    base = ' ' + formatError(value);
  }

  if (keys.length === 0 && (!array || value.length == 0)) {
    return braces[0] + base + braces[1];
  }

  if (recurseTimes < 0) {
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    } else {
      return ctx.stylize('[Object]', 'special');
    }
  }

  ctx.seen.push(value);

  var output;
  if (array) {
    output = formatArray(ctx, value, recurseTimes, visibleKeys, keys);
  } else {
    output = map(keys, function(key) {
      return formatProperty(ctx, value, recurseTimes, visibleKeys, key, array);
    });
  }

  ctx.seen.pop();

  return reduceToSingleString(output, base, braces);
}

function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
  var name, str, desc;
  desc = { value: void 0 };
  try {
    // ie6 › navigator.toString
    // throws Error: Object doesn't support this property or method
    desc.value = value[key];
  } catch (e) {
    // ignore
  }
  try {
    // ie10 › Object.getOwnPropertyDescriptor(window.location, 'hash')
    // throws TypeError: Object doesn't support this action
    if (Object.getOwnPropertyDescriptor) {
      desc = Object.getOwnPropertyDescriptor(value, key) || desc;
    }
  } catch (e) {
    // ignore
  }
  if (desc.get) {
    if (desc.set) {
      str = ctx.stylize('[Getter/Setter]', 'special');
    } else {
      str = ctx.stylize('[Getter]', 'special');
    }
  } else {
    if (desc.set) {
      str = ctx.stylize('[Setter]', 'special');
    }
  }
  if (!hasOwn(visibleKeys, key)) {
    name = '[' + key + ']';
  }
  if (!str) {
    if (indexOf(ctx.seen, desc.value) < 0) {
      if (isNull(recurseTimes)) {
        str = formatValue(ctx, desc.value, null);
      } else {
        str = formatValue(ctx, desc.value, recurseTimes - 1);
      }
      if (str.indexOf('\n') > -1) {
        if (array) {
          str = map(str.split('\n'), function(line) {
            return '  ' + line;
          }).join('\n').substr(2);
        } else {
          str = '\n' + map(str.split('\n'), function(line) {
            return '   ' + line;
          }).join('\n');
        }
      }
    } else {
      str = ctx.stylize('[Circular]', 'special');
    }
  }
  if (isUndefined(name)) {
    if (array && key.match(/^\d+$/)) {
      return str;
    }
    name = JSON.stringify('' + key);
    if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
      name = name.substr(1, name.length - 2);
      name = ctx.stylize(name, 'name');
    } else {
      name = name.replace(/'/g, "\\'")
                 .replace(/\\"/g, '"')
                 .replace(/(^"|"$)/g, "'");
      name = ctx.stylize(name, 'string');
    }
  }

  return name + ': ' + str;
}

function formatPrimitive(ctx, value) {
  if (isUndefined(value))
    return ctx.stylize('undefined', 'undefined');
  if (isString(value)) {
    var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
                                             .replace(/'/g, "\\'")
                                             .replace(/\\"/g, '"') + '\'';
    return ctx.stylize(simple, 'string');
  }
  if (isNumber(value))
    return ctx.stylize('' + value, 'number');
  if (isBoolean(value))
    return ctx.stylize('' + value, 'boolean');
  // For some reason typeof null is "object", so special case here.
  if (isNull(value))
    return ctx.stylize('null', 'null');
}

function reduceToSingleString(output, base, braces) {
  var numLinesEst = 0;
  var length = reduce(output, function(prev, cur) {
    numLinesEst++;
    if (cur.indexOf('\n') >= 0) numLinesEst++;
    return prev + cur.replace(/\u001b\[\d\d?m/g, '').length + 1;
  }, 0);

  if (length > 60) {
    return braces[0] +
           (base === '' ? '' : base + '\n ') +
           ' ' +
           output.join(',\n  ') +
           ' ' +
           braces[1];
  }

  return braces[0] + base + ' ' + output.join(', ') + ' ' + braces[1];
}

function _extend(origin, add) {
  // Don't do anything if add isn't an object
  if (!add || !isObject(add)) return origin;

  var keys = objectKeys(add);
  var i = keys.length;
  while (i--) {
    origin[keys[i]] = add[keys[i]];
  }
  return origin;
}