lodash/utility/attempt.js

define(['../lang/isError'], function(isError) {

  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
  var undefined;

  /**
   * Attempts to invoke `func`, returning either the result or the caught error
   * object. Any additional arguments are provided to `func` when it is invoked.
   *
   * @static
   * @memberOf _
   * @category Utility
   * @param {*} func The function to attempt.
   * @returns {*} Returns the `func` result or error object.
   * @example
   *
   * // avoid throwing errors for invalid selectors
   * var elements = _.attempt(function(selector) {
   *   return document.querySelectorAll(selector);
   * }, '>_>');
   *
   * if (_.isError(elements)) {
   *   elements = [];
   * }
   */
  function attempt() {
    var length = arguments.length,
        func = arguments[0];

    try {
      var args = Array(length ? length - 1 : 0);
      while (--length > 0) {
        args[length - 1] = arguments[length];
      }
      return func.apply(undefined, args);
    } catch(e) {
      return isError(e) ? e : new Error(e);
    }
  }

  return attempt;
});