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|
/* eslint-disable no-console */
import {
createStore,
combineReducers,
__DO_NOT_USE__ActionTypes as ActionTypes,
} from '../'
describe('Utils', () => {
describe('combineReducers', () => {
it('returns a composite reducer that maps the state keys to given reducers', () => {
const reducer = combineReducers({
counter: (state = 0, action) =>
action.type === 'increment' ? state + 1 : state,
stack: (state = [], action) =>
action.type === 'push' ? [...state, action.value] : state,
})
const s1 = reducer({}, { type: 'increment' })
expect(s1).toEqual({ counter: 1, stack: [] })
const s2 = reducer(s1, { type: 'push', value: 'a' })
expect(s2).toEqual({ counter: 1, stack: ['a'] })
})
it('ignores all props which are not a function', () => {
const reducer = combineReducers({
fake: true,
broken: 'string',
another: { nested: 'object' },
stack: (state = []) => state,
})
expect(Object.keys(reducer({}, { type: 'push' }))).toEqual(['stack'])
})
it('warns if a reducer prop is undefined', () => {
const preSpy = console.error
const spy = jest.fn()
console.error = spy
let isNotDefined
combineReducers({ isNotDefined })
expect(spy.mock.calls[0][0]).toMatch(
/No reducer provided for key "isNotDefined"/
)
spy.mockClear()
combineReducers({ thing: undefined })
expect(spy.mock.calls[0][0]).toMatch(
/No reducer provided for key "thing"/
)
spy.mockClear()
console.error = preSpy
})
it('throws an error if a reducer returns undefined handling an action', () => {
const reducer = combineReducers({
counter(state = 0, action) {
switch (action && action.type) {
case 'increment':
return state + 1
case 'decrement':
return state - 1
case 'whatever':
case null:
case undefined:
return undefined
default:
return state
}
},
})
expect(() => reducer({ counter: 0 }, { type: 'whatever' })).toThrow(
/"whatever".*"counter"/
)
expect(() => reducer({ counter: 0 }, null)).toThrow(
/"counter".*an action/
)
expect(() => reducer({ counter: 0 }, {})).toThrow(/"counter".*an action/)
})
it('throws an error on first call if a reducer returns undefined initializing', () => {
const reducer = combineReducers({
counter(state, action) {
switch (action.type) {
case 'increment':
return state + 1
case 'decrement':
return state - 1
default:
return state
}
},
})
expect(() => reducer({})).toThrow(/"counter".*initialization/)
})
it('catches error thrown in reducer when initializing and re-throw', () => {
const reducer = combineReducers({
throwingReducer() {
throw new Error('Error thrown in reducer')
},
})
expect(() => reducer({})).toThrow(/Error thrown in reducer/)
})
it('allows a symbol to be used as an action type', () => {
const increment = Symbol('INCREMENT')
const reducer = combineReducers({
counter(state = 0, action) {
switch (action.type) {
case increment:
return state + 1
default:
return state
}
},
})
expect(reducer({ counter: 0 }, { type: increment }).counter).toEqual(1)
})
it('maintains referential equality if the reducers it is combining do', () => {
const reducer = combineReducers({
child1(state = {}) {
return state
},
child2(state = {}) {
return state
},
child3(state = {}) {
return state
},
})
const initialState = reducer(undefined, '@@INIT')
expect(reducer(initialState, { type: 'FOO' })).toBe(initialState)
})
it('does not have referential equality if one of the reducers changes something', () => {
const reducer = combineReducers({
child1(state = {}) {
return state
},
child2(state = { count: 0 }, action) {
switch (action.type) {
case 'increment':
return { count: state.count + 1 }
default:
return state
}
},
child3(state = {}) {
return state
},
})
const initialState = reducer(undefined, '@@INIT')
expect(reducer(initialState, { type: 'increment' })).not.toBe(
initialState
)
})
it('throws an error on first call if a reducer attempts to handle a private action', () => {
const reducer = combineReducers({
counter(state, action) {
switch (action.type) {
case 'increment':
return state + 1
case 'decrement':
return state - 1
// Never do this in your code:
case ActionTypes.INIT:
return 0
default:
return undefined
}
},
})
expect(() => reducer()).toThrow(/"counter".*private/)
})
it('warns if no reducers are passed to combineReducers', () => {
const preSpy = console.error
const spy = jest.fn()
console.error = spy
const reducer = combineReducers({})
reducer({})
expect(spy.mock.calls[0][0]).toMatch(
/Store does not have a valid reducer/
)
spy.mockClear()
console.error = preSpy
})
it('warns if input state does not match reducer shape', () => {
const preSpy = console.error
const spy = jest.fn()
console.error = spy
const reducer = combineReducers({
foo(state = { bar: 1 }) {
return state
},
baz(state = { qux: 3 }) {
return state
},
})
reducer()
expect(spy.mock.calls.length).toBe(0)
reducer({ foo: { bar: 2 } })
expect(spy.mock.calls.length).toBe(0)
reducer({
foo: { bar: 2 },
baz: { qux: 4 },
})
expect(spy.mock.calls.length).toBe(0)
createStore(reducer, { bar: 2 })
expect(spy.mock.calls[0][0]).toMatch(
/Unexpected key "bar".*createStore.*instead: "foo", "baz"/
)
createStore(reducer, { bar: 2, qux: 4, thud: 5 })
expect(spy.mock.calls[1][0]).toMatch(
/Unexpected keys "qux", "thud".*createStore.*instead: "foo", "baz"/
)
createStore(reducer, 1)
expect(spy.mock.calls[2][0]).toMatch(
/createStore has unexpected type of "number".*keys: "foo", "baz"/
)
reducer({ corge: 2 })
expect(spy.mock.calls[3][0]).toMatch(
/Unexpected key "corge".*reducer.*instead: "foo", "baz"/
)
reducer({ fred: 2, grault: 4 })
expect(spy.mock.calls[4][0]).toMatch(
/Unexpected keys "fred", "grault".*reducer.*instead: "foo", "baz"/
)
reducer(1)
expect(spy.mock.calls[5][0]).toMatch(
/reducer has unexpected type of "number".*keys: "foo", "baz"/
)
spy.mockClear()
console.error = preSpy
})
it('only warns for unexpected keys once', () => {
const preSpy = console.error
const spy = jest.fn()
console.error = spy
const foo = (state = { foo: 1 }) => state
const bar = (state = { bar: 2 }) => state
expect(spy.mock.calls.length).toBe(0)
const reducer = combineReducers({ foo, bar })
const state = { foo: 1, bar: 2, qux: 3 }
reducer(state, {})
reducer(state, {})
reducer(state, {})
reducer(state, {})
expect(spy.mock.calls.length).toBe(1)
reducer({ ...state, baz: 5 }, {})
reducer({ ...state, baz: 5 }, {})
reducer({ ...state, baz: 5 }, {})
reducer({ ...state, baz: 5 }, {})
expect(spy.mock.calls.length).toBe(2)
spy.mockClear()
console.error = preSpy
})
describe('With Replace Reducers', function () {
const foo = (state = {}) => state
const bar = (state = {}) => state
const ACTION = { type: 'ACTION' }
it('should return an updated state when additional reducers are passed to combineReducers', function () {
const originalCompositeReducer = combineReducers({ foo })
const store = createStore(originalCompositeReducer)
store.dispatch(ACTION)
const initialState = store.getState()
store.replaceReducer(combineReducers({ foo, bar }))
store.dispatch(ACTION)
const nextState = store.getState()
expect(nextState).not.toBe(initialState)
})
it('should return an updated state when reducers passed to combineReducers are changed', function () {
const baz = (state = {}) => state
const originalCompositeReducer = combineReducers({ foo, bar })
const store = createStore(originalCompositeReducer)
store.dispatch(ACTION)
const initialState = store.getState()
store.replaceReducer(combineReducers({ baz, bar }))
store.dispatch(ACTION)
const nextState = store.getState()
expect(nextState).not.toBe(initialState)
})
it('should return the same state when reducers passed to combineReducers not changed', function () {
const originalCompositeReducer = combineReducers({ foo, bar })
const store = createStore(originalCompositeReducer)
store.dispatch(ACTION)
const initialState = store.getState()
store.replaceReducer(combineReducers({ foo, bar }))
store.dispatch(ACTION)
const nextState = store.getState()
expect(nextState).toBe(initialState)
})
it('should return an updated state when one of more reducers passed to the combineReducers are removed', function () {
const originalCompositeReducer = combineReducers({ foo, bar })
const store = createStore(originalCompositeReducer)
store.dispatch(ACTION)
const initialState = store.getState()
store.replaceReducer(combineReducers({ bar }))
const nextState = store.getState()
expect(nextState).not.toBe(initialState)
})
})
})
})
|
