lodash/lodash.iserror/index.js

/** `Object#toString` result references. */

/** `Object#toString` result references. */
var errorTag = '[object Error]';

/**
 * Checks if `value` is object-like.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
 */
function isObjectLike(value) {
  return !!value && typeof value == 'object';
}

/** Used for native method references. */
var objectProto = Object.prototype;

/**
 * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
 * of values.
 */
var objToString = objectProto.toString;

/**
 * Checks if `value` is an `Error`, `EvalError`, `RangeError`, `ReferenceError`,
 * `SyntaxError`, `TypeError`, or `URIError` object.
 *
 * @static
 * @memberOf _
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is an error object, else `false`.
 * @example
 *
 * _.isError(new Error);
 * // => true
 *
 * _.isError(Error);
 * // => false
 */
function isError(value) {
  return isObjectLike(value) && typeof value.message == 'string' && objToString.call(value) == errorTag;
}

module.exports = isError;