Why does my arrow function have a prototype property?

问题

As mention in document https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Functions/Arrow_functions

Arrow functions do not have prototype property

but when I run this on fiddle, why does it gives an object? http://es6console.com/iwyii5vm/

Why it is giving a object?

var Foo = () => {};
console.log(Foo.prototype); 

回答1:

If you run this code in a native ES6 engine, there will not be a prototype property for arrow functions.

Example of native ES6:

var Foo = () => {};
console.log(Foo.prototype); 

However, if the code is being transpiled to ES5 code, it will not be a true arrow function, and it will have a prototype property.

Example of ES6 being transpiled with Babel:

(Babel is enabled for this snippet)

var Foo = () => {};
console.log(Foo.prototype);

In the case of es6console.com, a transpiler is being used, which is why you are seeing this behavior.

回答2:

This seems to be an implementation detail of the way es6console implements es6 features. It works correctly in Chrome, which natively supports arrow functions.

来源：https://stackoverflow.com/questions/41255943/why-does-my-arrow-function-have-a-prototype-property