116 lines
3.3 KiB
JavaScript
116 lines
3.3 KiB
JavaScript
import brcast from './index'
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test('default export is a function', () => {
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expect(typeof brcast).toBe('function')
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})
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test('exposes the public API', () => {
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const broadcast = brcast()
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const methods = Object.keys(broadcast)
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expect(methods.length).toBe(4)
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expect(methods).toContain('subscribe')
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expect(methods).toContain('unsubscribe')
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expect(methods).toContain('getState')
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expect(methods).toContain('setState')
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})
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test('throws if listener is not a function', () => {
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const broadcast = brcast()
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expect(() => broadcast.subscribe()).toThrow()
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expect(() => broadcast.subscribe('throw')).toThrow()
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expect(() => broadcast.subscribe({})).toThrow()
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expect(() => broadcast.subscribe(() => {})).not.toThrow()
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})
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test('is able to start with an undefined state and update it accordingly', () => {
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const broadcast = brcast()
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expect(broadcast.getState()).toBeUndefined()
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broadcast.setState(2)
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expect(broadcast.getState()).toBe(2)
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})
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test('it updates the state', () => {
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const handler = jest.fn()
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const broadcast = brcast()
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broadcast.subscribe(handler)
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broadcast.setState(2)
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expect(handler.mock.calls.length).toBe(1)
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expect(handler.mock.calls[0][0]).toBe(2)
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})
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test('it unsubscribes only relevant listeners', () => {
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const handler = jest.fn()
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const handler1 = jest.fn()
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const broadcast = brcast(1)
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const subscriptionId = broadcast.subscribe(handler)
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broadcast.subscribe(handler1)
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broadcast.unsubscribe(subscriptionId)
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broadcast.setState(2)
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broadcast.setState(3)
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expect(handler.mock.calls.length).toBe(0)
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expect(handler1.mock.calls.length).toBe(2)
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})
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test('removes listeners only once when unsubscribing more than once', () => {
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const handler = jest.fn()
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const broadcast = brcast(1)
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const subscriptionId = broadcast.subscribe(handler)
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broadcast.unsubscribe(subscriptionId)
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broadcast.unsubscribe(subscriptionId)
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broadcast.setState(2)
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expect(handler.mock.calls.length).toBe(0)
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})
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test('supports removing a subscription within a subscription', () => {
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const broadcast = brcast(1)
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const handler = jest.fn()
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const handler1 = jest.fn()
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const handler2 = jest.fn()
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broadcast.subscribe(handler)
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const sub1Id = broadcast.subscribe(() => {
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handler1()
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broadcast.unsubscribe(sub1Id)
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})
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broadcast.subscribe(handler2)
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broadcast.setState(2)
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broadcast.setState(3)
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expect(handler.mock.calls.length).toBe(2)
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expect(handler1.mock.calls.length).toBe(1)
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expect(handler2.mock.calls.length).toBe(2)
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})
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test('do not notify subscribers getting unsubscribed in the middle of a setState', () => {
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const broadcast = brcast()
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const unsubscribeIds = []
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const doUnsubscribeAll = () =>
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unsubscribeIds.forEach(id => broadcast.unsubscribe(id))
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const handler = jest.fn()
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const handler1 = jest.fn()
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const handler2 = jest.fn()
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unsubscribeIds.push(broadcast.subscribe(handler))
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unsubscribeIds.push(
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broadcast.subscribe(() => {
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handler1()
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doUnsubscribeAll()
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})
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)
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unsubscribeIds.push(broadcast.subscribe(handler2))
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broadcast.setState(2)
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expect(handler.mock.calls.length).toBe(1)
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expect(handler1.mock.calls.length).toBe(1)
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expect(handler2.mock.calls.length).toBe(0)
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broadcast.setState(3)
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expect(handler.mock.calls.length).toBe(1)
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expect(handler1.mock.calls.length).toBe(1)
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expect(handler2.mock.calls.length).toBe(0)
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})
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