lodash/isError.js

import isObjectLike from './isObjectLike';

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

/** Used for built-in 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 objectToString = 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) {
  if (!isObjectLike(value)) {
    return false;
  }
  var Ctor = value.constructor;
  return (objectToString.call(value) == errorTag) ||
    (typeof Ctor == 'function' && objectToString.call(Ctor.prototype) == errorTag);
}

export default isError;