autocast/index.js

Easily and automatically cast common datatypes in JavaScript

(function() {
  /**
   * Common strings to cast
   */
  var common_strings = {
    'true': true,
    'false': false,
    'undefined': undefined,
    'null': null,
    'NaN': NaN
  };

  /**
   * Given a value, try and cast it
   */
  function autocast(s) {
    var key;

    // Don't cast Date objects
    if (s instanceof Date) return s;

    // Try to cast it to a number
    if ((key = +s) == key) return key;

    // Try to make it a common string
    for (key in common_strings) {
      if (s === key) return common_strings[key];
    }

    // Give up
    return s;
  };

  // export
  if (typeof exports === 'undefined') {
    window.autocast = autocast;
  } else {
    module.exports = autocast;
  }
}());