How can I spy on a getter property using jasmine?

javascript jasmine
Ben Aston picture Ben Aston · Oct 15, 2015 · Viewed 30.1k times · Source

How can I spy on a getter property using jasmine?

var o = { get foo() {}, };

spyOn(o, 'foo').and.returnValue('bar'); // Doesn't work.

This also does not work AFAICT:

spyOn(Object.getOwnPropertyDescriptor(o, 'foo'), 'get').and.returnValue('bar');

Answer

apsillers picture apsillers · Oct 16, 2015

Since Jasmine 2.6, this has been possible with spyOnProperty. To spy on the accessors for the foo property, do:

spyOnProperty(o, 'foo')

This allows you to replace the set and/or get accessor functions for an accessor property with a spy function. You can specify or set or get only as a third argument:

spyOnProperty(o, 'foo', 'get')

If you are stuck using an earlier version and cannot upgrade for some reason, you may be able to merge the pull request that added this feature into your local copy of the code.

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