Unit test for array with .find method in angular using jest

Question

How to get coverage for array with .find method in angular. I'm getting trouble in the below piece of code.

sample.component.ts

public permissions = [{id: 0, value: 'fruit' }, {id: 1, value: 'vegetable'}];
this.filteredList = this.permissions.slice();
public isFiltered(permission) {
    return this.filteredList.find(item => item.id === permission.id);
}

sample.spec.ts

it('should call myMethod ', () => {
  expect(component.isFiltered(1)).toEqual(true);
});

I'm getting the following error , TypeError: Cannot read property 'find' of undefined

Any help would be appreciated

Shlok Nangia · Accepted Answer · 2020-05-27 14:32:01Z

1

write it like this

 it('should call myMethod ', () => {
   let permissions = [{id: 0, value: 'fruit' },{id: 1, value: 'vegetable'} ];
   component.filteredList = permissions.slice();
   expect(component.isFiltered({id:1}).value).toEqual('vegetable');
 });

You need to give some value to component.filteredList

UPDATE

as you are using persmissions.id in your ts to filter you need to pass an object with property id(to filter by) to isFiltered(). Also isFiltered does not returns a boolean but the object (i.e. search result itself) so we check its value to be the required one

edited May 27, 2020 at 14:32

answered May 27, 2020 at 11:17

Shlok Nangia

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2 Comments

Christina Varghese Over a year ago

this is not working for me.Running into previous error itself.Could you please post a working code.

Shlok Nangia Over a year ago

Happy to help :-)

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