How to unit test angular method having HTMLInputElement as parameter?

user_4719318 0
Viewed 937

Below is my code snippet

code

applyFilter(event: Event): void {
        const filterValue = (event.target as HTMLInputElement).value;
        this.filterBy = filterValue.trim().toLowerCase();
        this.dataSource.filter = filterValue.trim().toLowerCase();
    }

Test cases

 fit('applyFilter', () => {
        const event = new Event('click');
        component.applyFilter(event);
    });

Error i am getting is "TypeError: Cannot read property 'value' of null" while this conversion "(event.target as HTMLInputElement).value;" meentioned error is occuring

jasmine angular unit-testing
1 Answers

I would just mock the object.

it('should change filterBy and dataSource.filter', () => {
  const event = { target: { value: 'hello' } } as any;
  component.applyFilter(event);
  expect(component.filterBy).toBe('hello');
  expect(component.dataSource.filter).toBe('hello');
});
user_73654610
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