'use strict'; var isCallable = require('is-callable'); var fnToStr = Function.prototype.toString; var isNonArrowFnRegex = /^\s*function/; var isArrowFnWithParensRegex = /^\([^\)]*\) *=>/; var isArrowFnWithoutParensRegex = /^[^=]*=>/; module.exports = function isArrowFunction(fn) { if (!isCallable(fn)) { return false; } var fnStr = fnToStr.call(fn); return fnStr.length > 0 && !isNonArrowFnRegex.test(fnStr) && (isArrowFnWithParensRegex.test(fnStr) || isArrowFnWithoutParensRegex.test(fnStr)); };