angular-docs-cn/modules/change_detection/test/array_changes_spec.js

import {describe, it, iit, xit, expect, beforeEach, afterEach} from 'test_lib/test_lib';
import {ArrayChanges} from 'change_detection/array_changes';
import {NumberWrapper} from 'facade/lang';
import {ListWrapper, MapWrapper} from 'facade/collection';
import {TestIterable} from './iterable';
import {arrayChangesAsString} from './util';

// todo(vicb): UnmodifiableListView / frozen object when implemented
export function main() {
  describe('collection_changes', function() {
    describe('CollectionChanges', function() {
      var changes;
      var l;

      beforeEach(() => {
        changes = new ArrayChanges();
      });

      afterEach(() => {
        changes = null;
      });

      it('should support list and iterables', () => {
        expect(ArrayChanges.supports([])).toBeTruthy();
        expect(ArrayChanges.supports(new TestIterable())).toBeTruthy();
        expect(ArrayChanges.supports(MapWrapper.create())).toBeFalsy();
        expect(ArrayChanges.supports(null)).toBeFalsy();
      });

      it('should support iterables', () => {
        l = new TestIterable();

        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: []
        }));

        l.list = [1];
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['1[null->0]'],
          additions: ['1[null->0]']
        }));

        l.list = [2, 1];
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['2[null->0]', '1[0->1]'],
          previous: ['1[0->1]'],
          additions: ['2[null->0]'],
          moves: ['1[0->1]']
        }));
      });

      it('should detect additions', () => {
        l = [];
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: []
        }));

        ListWrapper.push(l, 'a');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['a[null->0]'],
          additions: ['a[null->0]']
        }));

        ListWrapper.push(l, 'b');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['a', 'b[null->1]'],
          previous: ['a'],
          additions: ['b[null->1]']
        }));
      });

      it('should support changing the reference', () => {
        l = [0];
        changes.check(l);

        l = [1, 0];
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['1[null->0]', '0[0->1]'],
          previous: ['0[0->1]'],
          additions: ['1[null->0]'],
          moves: ['0[0->1]']
        }));

        l = [2, 1, 0];
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['2[null->0]', '1[0->1]', '0[1->2]'],
          previous: ['1[0->1]', '0[1->2]'],
          additions: ['2[null->0]'],
          moves: ['1[0->1]', '0[1->2]']
        }));
      });

      it('should handle swapping element', () => {
        l = [1, 2];
        changes.check(l);

        ListWrapper.clear(l);
        ListWrapper.push(l, 2);
        ListWrapper.push(l, 1);
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['2[1->0]', '1[0->1]'],
          previous: ['1[0->1]', '2[1->0]'],
          moves: ['2[1->0]', '1[0->1]']
        }));
      });

      it('should handle swapping element', () => {
        l = ['a', 'b', 'c'];
        changes.check(l);

        ListWrapper.removeAt(l, 1);
        ListWrapper.insert(l, 0, 'b');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['b[1->0]', 'a[0->1]', 'c'],
          previous: ['a[0->1]', 'b[1->0]', 'c'],
          moves: ['b[1->0]', 'a[0->1]']
        }));

        ListWrapper.removeAt(l, 1);
        ListWrapper.push(l, 'a');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['b', 'c[2->1]', 'a[1->2]'],
          previous: ['b', 'a[1->2]', 'c[2->1]'],
          moves: ['c[2->1]', 'a[1->2]']
        }));
      });

      it('should detect changes in list', () => {
        l = [];
        changes.check(l);

        ListWrapper.push(l, 'a');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['a[null->0]'],
          additions: ['a[null->0]']
        }));

        ListWrapper.push(l, 'b');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['a', 'b[null->1]'],
          previous: ['a'],
          additions: ['b[null->1]']
        }));

        ListWrapper.push(l, 'c');
        ListWrapper.push(l, 'd');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['a', 'b', 'c[null->2]', 'd[null->3]'],
          previous: ['a', 'b'],
          additions: ['c[null->2]', 'd[null->3]']
        }));

        ListWrapper.removeAt(l, 2);
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['a', 'b', 'd[3->2]'],
          previous: ['a', 'b', 'c[2->null]', 'd[3->2]'],
          moves: ['d[3->2]'],
          removals: ['c[2->null]']
        }));

        ListWrapper.clear(l);
        ListWrapper.push(l, 'd');
        ListWrapper.push(l, 'c');
        ListWrapper.push(l, 'b');
        ListWrapper.push(l, 'a');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['d[2->0]', 'c[null->1]', 'b[1->2]', 'a[0->3]'],
          previous: ['a[0->3]', 'b[1->2]', 'd[2->0]'],
          additions: ['c[null->1]'],
          moves: ['d[2->0]', 'b[1->2]', 'a[0->3]']
        }));
      });

      it('should test string by value rather than by reference (Dart)', () => {
        l = ['a', 'boo'];
        changes.check(l);

        var b = 'b';
        var oo = 'oo';
        ListWrapper.set(l, 1, b + oo);
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['a', 'boo'],
          previous: ['a', 'boo']
        }));
      });

      it('should ignore [NaN] != [NaN] (JS)', () => {
        l = [NumberWrapper.NaN];
        changes.check(l);
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: [NumberWrapper.NaN],
          previous: [NumberWrapper.NaN]
        }));
      });

      it('should detect [NaN] moves', () => {
        l = [NumberWrapper.NaN, NumberWrapper.NaN];
        changes.check(l);

        ListWrapper.insert(l, 0, 'foo');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
            collection: ['foo[null->0]', 'NaN[0->1]', 'NaN[1->2]'],
            previous: ['NaN[0->1]', 'NaN[1->2]'],
            additions: ['foo[null->0]'],
            moves: ['NaN[0->1]', 'NaN[1->2]']}
        ));
      });

      it('should remove and add same item', () => {
        l = ['a', 'b', 'c'];
        changes.check(l);

        ListWrapper.removeAt(l, 1);
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['a', 'c[2->1]'],
          previous: ['a', 'b[1->null]', 'c[2->1]'],
          moves: ['c[2->1]'],
          removals: ['b[1->null]']
        }));

        ListWrapper.insert(l, 1, 'b');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['a', 'b[null->1]', 'c[1->2]'],
          previous: ['a', 'c[1->2]'],
          additions: ['b[null->1]'],
          moves: ['c[1->2]']
        }));
      });

      it('should support duplicates', () => {
        l = ['a', 'a', 'a', 'b', 'b'];
        changes.check(l);

        ListWrapper.removeAt(l, 0);
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['a', 'a', 'b[3->2]', 'b[4->3]'],
          previous: ['a', 'a', 'a[2->null]', 'b[3->2]', 'b[4->3]'],
          moves: ['b[3->2]', 'b[4->3]'],
          removals: ['a[2->null]']
        }));
      });

      it('should support insertions/moves', () => {
        l = ['a', 'a', 'b', 'b'];
        changes.check(l);

        ListWrapper.insert(l, 0, 'b');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['b[2->0]', 'a[0->1]', 'a[1->2]', 'b', 'b[null->4]'],
          previous: ['a[0->1]', 'a[1->2]', 'b[2->0]', 'b'],
          additions: ['b[null->4]'],
          moves: ['b[2->0]', 'a[0->1]', 'a[1->2]']
        }));
      });

      it('should not report unnecessary moves', () => {
        l = ['a', 'b', 'c'];
        changes.check(l);

        ListWrapper.clear(l);
        ListWrapper.push(l, 'b');
        ListWrapper.push(l, 'a');
        ListWrapper.push(l, 'c');
        changes.check(l);
        expect(changes.toString()).toEqual(arrayChangesAsString({
          collection: ['b[1->0]', 'a[0->1]', 'c'],
          previous: ['a[0->1]', 'b[1->0]', 'c'],
          moves: ['b[1->0]', 'a[0->1]']
        }));
      });
    });
  });
}