quick and dirty implementation of JSON.stringify in JavaScript

json_stringify.js

;(function () {
  'use strict';

  var UNSAFE_STR_REGEX = /[\n\r]+/;

  var SUPPORTED_TYPES = [
    'array',
    'object',
    'boolean',
    'string',
    'number'
  ];

  function contains (array, item) {
    return array.indexOf(item) !== -1;
  }

  function getType (obj) {
    var type = Array.isArray(obj) ? 'array' : typeof obj;

    if (contains(SUPPORTED_TYPES, type)) {
      return type;
    }
    else {
      throw new TypeError('only types: <' + SUPPORTED_TYPES.join(',') + '> are supported');
    }

  }

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

  function stringify (obj) {
    var str;
    var keys;
    var noFuncKeys;

    switch (getType(obj)) {
    case 'string':
      str = '"' + obj.replace(UNSAFE_STR_REGEX, '') + '"';
      break;

    case 'boolean':
      str = '"' + obj.toString() + '"';
      break;

    case 'number':
      str = obj.toString();
      break;

    case 'array':
      str = '[' + obj.map(stringify).join(', ') + ']';
      break;

    default:
      keys = Object.keys(obj);
      noFuncKeys = keys.filter(function (k) {
        return !isFunction(obj[k]);
      });

      str = '{' + noFuncKeys.map(function (k) { return stringify(k) + ':' + stringify(obj[k]); }) + '}';
      break;
    }

    return str;

  }

  if (module && module.exports) {
    module.exports = stringify;
    global.stringify = stringify;
  }
  else {
    this.stringify = stringify;
  }

})();