portfolio/packages/frptools/spec/property.spec.js
2018-03-28 14:18:17 -05:00

103 lines
2.5 KiB
JavaScript

import { prop } from '../src/index.js';
import { dirtyMock, hashSet } from '../src/testUtil.js';
describe('A property', () => {
it('returns its initialized value', () => {
const a = prop(true);
expect(a()).toEqual(true);
});
it('returns its set value', () => {
const a = prop();
expect(a()).toEqual(undefined);
expect(a(true)).toEqual(true);
});
it('returns notifies dependents of updates', () => {
let runCount = 0;
let currentValue = 1;
const a = prop();
a.subscribe(val => {
runCount += 1;
expect(val).toEqual(currentValue);
});
expect(a(1)).toEqual(1);
expect(runCount).toEqual(1);
expect(a(1)).toEqual(1);
expect(runCount).toEqual(1);
currentValue = 2;
expect(a(2)).toEqual(2);
expect(runCount).toEqual(2);
expect(a(2)).toEqual(2);
expect(runCount).toEqual(2);
currentValue = 1;
expect(a(1)).toEqual(1);
expect(runCount).toEqual(3);
expect(a(1)).toEqual(1);
expect(runCount).toEqual(3);
});
it('honors cancelled subscriptions', () => {
let runCount = 0;
let currentValue = 1;
const a = prop();
const cancelSubscription = a.subscribe(val => {
runCount += 1;
expect(val).toEqual(currentValue);
});
const cancelSubscription2 = a.subscribe(val => {
runCount += 1;
expect(val).toEqual(currentValue);
});
expect(a(1)).toEqual(1);
expect(runCount).toEqual(2);
expect(a(1)).toEqual(1);
expect(runCount).toEqual(2);
expect(cancelSubscription()).toEqual(1);
currentValue = 3;
expect(a(3)).toEqual(3);
expect(runCount).toEqual(3);
expect(cancelSubscription2()).toEqual(0);
currentValue = 4;
expect(a(4)).toEqual(4);
expect(runCount).toEqual(3);
});
it('uses a hash function', () => {
let runCount = 0;
const a = prop(new Set([1, 2]), hashSet);
a.subscribe(() => (runCount += 1));
expect([...a()]).toEqual([1, 2]);
expect(runCount).toEqual(0);
expect([...a(new Set([2, 1]))]).toEqual([1, 2]);
expect(runCount).toEqual(0);
expect([...a(new Set([3, 2, 1]))]).toEqual([3, 2, 1]);
expect(runCount).toEqual(1);
});
it('flags all subscribers as dirty before propagating change', () => {
const a = prop(true);
const [dirtyA, dirtyB, checker] = dirtyMock(2);
a.subscribe(dirtyA.setDirty);
a.subscribe(dirtyB.setDirty);
a(false);
expect(checker()).toBe(true);
});
it('calls subscriptions in order', () => {
let order = '';
const a = prop(0);
a.subscribe(() => (order += 'a'));
a.subscribe(() => (order += 'b'));
a.subscribe(() => (order += 'c'));
a(1);
expect(order).toEqual('abc');
});
});