Stubbing an ES6 class method using Mocha and Sinon in NodeJS

Question

Is there a way to stub an ES6 class method using Mocha/Sinon?

I'm trying to do this...

sinon.stub(Factory, 'announce');

but I just get the following error...

TypeError: Attempted to wrap undefined property announce as function

Shouldn't you pass `Factory.prototype`? I guess it's not a static method. — Bergi, May 27 '16 at 00:01
I didn't realise that ES6 classes still used .prototype! Want to post an answer for me to accept? — michael, May 27 '16 at 12:02

score 22 · Accepted Answer · answered May 27 '16 at 12:11

22

Instance methods are still placed on the prototype object of a class to be inherited from, not on its constructor, even if the class syntax obscures that a bit. Use

sinon.stub(Factory.prototype, 'announce');

answered May 27 '16 at 12:11

Bergi

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and you can use `stub(obj, 'meth').callsFake(fn)` if you need to override the function. https://sinonjs.org/releases/v6.1.5/stubs/ – mikey Aug 16 '18 at 00:50

Stubbing an ES6 class method using Mocha and Sinon in NodeJS

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