4744c229db
Even in the overloads, state that it can accept `null` and `undefined`, in order to ensure easy composition with `async`. Additionally, change the implementation to return `null` on an `undefined` input, for consistency with other pipes. BREAKING CHANGE: The `slice` pipe now returns `null` for the `undefined` input value, which is consistent with the behavior of most pipes. If you rely on `undefined` being the result in that case, you now need to check for it explicitly. PR Close #37447
122 lines
4.1 KiB
TypeScript
122 lines
4.1 KiB
TypeScript
/**
|
|
* @license
|
|
* Copyright Google LLC All Rights Reserved.
|
|
*
|
|
* Use of this source code is governed by an MIT-style license that can be
|
|
* found in the LICENSE file at https://angular.io/license
|
|
*/
|
|
|
|
import {CommonModule, SlicePipe} from '@angular/common';
|
|
import {Component} from '@angular/core';
|
|
import {TestBed, waitForAsync} from '@angular/core/testing';
|
|
import {expect} from '@angular/platform-browser/testing/src/matchers';
|
|
|
|
{
|
|
describe('SlicePipe', () => {
|
|
let list: number[];
|
|
let str: string;
|
|
let pipe: SlicePipe;
|
|
|
|
beforeEach(() => {
|
|
list = [1, 2, 3, 4, 5];
|
|
str = 'tuvwxyz';
|
|
pipe = new SlicePipe();
|
|
});
|
|
|
|
describe('supports', () => {
|
|
it('should support strings', () => {
|
|
expect(() => pipe.transform(str, 0)).not.toThrow();
|
|
});
|
|
it('should support lists', () => {
|
|
expect(() => pipe.transform(list, 0)).not.toThrow();
|
|
});
|
|
it('should support readonly lists', () => {
|
|
expect(() => pipe.transform(list as ReadonlyArray<number>, 0)).not.toThrow();
|
|
});
|
|
|
|
it('should not support other objects',
|
|
// this would not compile
|
|
// so we cast as `any` to check that it throws for unsupported objects
|
|
() => {
|
|
expect(() => pipe.transform({} as any, 0)).toThrow();
|
|
});
|
|
});
|
|
|
|
describe('transform', () => {
|
|
it('should return null if the value is null', () => {
|
|
expect(pipe.transform(null, 1)).toBe(null);
|
|
});
|
|
|
|
it('should return null if the value is undefined', () => {
|
|
expect(pipe.transform(undefined, 1)).toBe(null);
|
|
});
|
|
|
|
it('should return all items after START index when START is positive and END is omitted',
|
|
() => {
|
|
expect(pipe.transform(list, 3)).toEqual([4, 5]);
|
|
expect(pipe.transform(str, 3)).toEqual('wxyz');
|
|
});
|
|
|
|
it('should return last START items when START is negative and END is omitted', () => {
|
|
expect(pipe.transform(list, -3)).toEqual([3, 4, 5]);
|
|
expect(pipe.transform(str, -3)).toEqual('xyz');
|
|
});
|
|
|
|
it('should return all items between START and END index when START and END are positive',
|
|
() => {
|
|
expect(pipe.transform(list, 1, 3)).toEqual([2, 3]);
|
|
expect(pipe.transform(str, 1, 3)).toEqual('uv');
|
|
});
|
|
|
|
it('should return all items between START and END from the end when START and END are negative',
|
|
() => {
|
|
expect(pipe.transform(list, -4, -2)).toEqual([2, 3]);
|
|
expect(pipe.transform(str, -4, -2)).toEqual('wx');
|
|
});
|
|
|
|
it('should return an empty value if START is greater than END', () => {
|
|
expect(pipe.transform(list, 4, 2)).toEqual([]);
|
|
expect(pipe.transform(str, 4, 2)).toEqual('');
|
|
});
|
|
|
|
it('should return an empty value if START greater than input length', () => {
|
|
expect(pipe.transform(list, 99)).toEqual([]);
|
|
expect(pipe.transform(str, 99)).toEqual('');
|
|
});
|
|
|
|
it('should return entire input if START is negative and greater than input length', () => {
|
|
expect(pipe.transform(list, -99)).toEqual([1, 2, 3, 4, 5]);
|
|
expect(pipe.transform(str, -99)).toEqual('tuvwxyz');
|
|
});
|
|
|
|
it('should not modify the input list', () => {
|
|
expect(pipe.transform(list, 2)).toEqual([3, 4, 5]);
|
|
expect(list).toEqual([1, 2, 3, 4, 5]);
|
|
});
|
|
});
|
|
|
|
describe('integration', () => {
|
|
@Component({selector: 'test-comp', template: '{{(data | slice:1).join(",") }}'})
|
|
class TestComp {
|
|
data: any;
|
|
}
|
|
|
|
beforeEach(() => {
|
|
TestBed.configureTestingModule({declarations: [TestComp], imports: [CommonModule]});
|
|
});
|
|
|
|
it('should work with mutable arrays', waitForAsync(() => {
|
|
const fixture = TestBed.createComponent(TestComp);
|
|
const mutable: number[] = [1, 2];
|
|
fixture.componentInstance.data = mutable;
|
|
fixture.detectChanges();
|
|
expect(fixture.nativeElement).toHaveText('2');
|
|
|
|
mutable.push(3);
|
|
fixture.detectChanges();
|
|
expect(fixture.nativeElement).toHaveText('2,3');
|
|
}));
|
|
});
|
|
});
|
|
}
|