minErr.js

'use strict';

/**
 * @description
 *
 * This object provides a utility for producing rich Error messages within
 * Angular. It can be called as follows:
 *
 * var exampleMinErr = minErr('example');
 * throw exampleMinErr('one', 'This {0} is {1}', foo, bar);
 *
 * The above creates an instance of minErr in the example namespace. The
 * resulting error will have a namespaced error code of example.one.  The
 * resulting error will replace {0} with the value of foo, and {1} with the
 * value of bar. The object is not restricted in the number of arguments it can
 * take.
 *
 * If fewer arguments are specified than necessary for interpolation, the extra
 * interpolation markers will be preserved in the final string.
 *
 * Since data will be parsed statically during a build step, some restrictions
 * are applied with respect to how minErr instances are created and called.
 * Instances should have names of the form namespaceMinErr for a minErr created
 * using minErr('namespace') . Error codes, namespaces and template strings
 * should all be static strings, not variables or general expressions.
 *
 * @param {string} module The namespace to use for the new minErr instance.
 * @returns {function(string, string, ...): Error} instance
 */

function minErr(module) {
  return function () {
    var prefix = '[' + (module ? module + ':' : '') + arguments[0] + '] ',
      template = arguments[1],
      templateArgs = arguments,
      message;

    message = prefix + template.replace(/\{\d+\}/g, function (match) {
      var index = +match.slice(1, -1), arg;

      if (index + 2 < templateArgs.length) {
        arg = templateArgs[index + 2];
        if (isFunction(arg)) {
          return arg.toString().replace(/ ?\{[\s\S]*$/, '');
        } else if (isUndefined(arg)) {
          return 'undefined';
        } else if (!isString(arg)) {
          return toJson(arg);
        }
        return arg;
      }
      return match;
    });

    return new Error(message);
  };
}