DisplayMessages
.
render()
компонент визуализирует элемент input
элемент button
элемент ul
. Когда элемент input
изменяется, он должен вызвать метод handleChange()
. Кроме того, элемент input
должен отображать значение input
, находящееся в состоянии компонента. Элемент button
должен запускать метод submitMessage()
при нажатии. Во-вторых, напишите эти два метода. Метод handleChange()
должен обновлять input
с помощью input
пользователем. Метод submitMessage()
должен конкатенировать текущее сообщение (сохраненное на input
) в массив messages
в локальном состоянии и очистить значение input
. Наконец, используйте ul
для сопоставления массива messages
и отображения его на экране в виде списка элементов li
.
DisplayMessages
component should initialize with a state equal to { input: "", messages: [] }
.'
testString: assert((function() { const mockedComponent = Enzyme.mount(React.createElement(DisplayMessages)); const initialState = mockedComponent.state(); return ( typeof initialState === 'object' && initialState.input === '' && initialState.messages.length === 0); })());
- text: The DisplayMessages
component should render a div
containing an h2
element, a button
element, a ul
element, and li
elements as children.
testString: 'async () => { const mockedComponent = Enzyme.mount(React.createElement(DisplayMessages)); const waitForIt = (fn) => new Promise((resolve, reject) => setTimeout(() => resolve(fn()), 100)); const state = () => { mockedComponent.setState({messages: [''__TEST__MESSAGE'']}); return waitForIt(() => mockedComponent )}; const updated = await state(); assert(updated.find(''div'').length === 1 && updated.find(''h2'').length === 1 && updated.find(''button'').length === 1 && updated.find(''ul'').length === 1 && updated.find(''li'').length > 0); }; '
- text: .map
was used on the messages
array.
testString: assert(code.match(/this\.state\.messages\.map/g));
- text: The input
element should render the value of input
in local state.
testString: 'async () => { const mockedComponent = Enzyme.mount(React.createElement(DisplayMessages)); const waitForIt = (fn) => new Promise((resolve, reject) => setTimeout(() => resolve(fn()), 100)); const causeChange = (c, v) => c.find(''input'').simulate(''change'', { target: { value: v }}); const testValue = ''__TEST__EVENT__INPUT''; const changed = () => { causeChange(mockedComponent, testValue); return waitForIt(() => mockedComponent )}; const updated = await changed(); assert(updated.find(''input'').props().value === testValue); }; '
- text: Calling the method handleChange
should update the input
value in state to the current input.
testString: 'async () => { const mockedComponent = Enzyme.mount(React.createElement(DisplayMessages)); const waitForIt = (fn) => new Promise((resolve, reject) => setTimeout(() => resolve(fn()), 100)); const causeChange = (c, v) => c.find(''input'').simulate(''change'', { target: { value: v }}); const initialState = mockedComponent.state(); const testMessage = ''__TEST__EVENT__MESSAGE__''; const changed = () => { causeChange(mockedComponent, testMessage); return waitForIt(() => mockedComponent )}; const afterInput = await changed(); assert(initialState.input === '''' && afterInput.state().input === ''__TEST__EVENT__MESSAGE__''); }; '
- text: Clicking the Add message
button should call the method submitMessage
which should add the current input
to the messages
array in state.
testString: 'async () => { const mockedComponent = Enzyme.mount(React.createElement(DisplayMessages)); const waitForIt = (fn) => new Promise((resolve, reject) => setTimeout(() => resolve(fn()), 100)); const causeChange = (c, v) => c.find(''input'').simulate(''change'', { target: { value: v }}); const initialState = mockedComponent.state(); const testMessage_1 = ''__FIRST__MESSAGE__''; const firstChange = () => { causeChange(mockedComponent, testMessage_1); return waitForIt(() => mockedComponent )}; const firstResult = await firstChange(); const firstSubmit = () => { mockedComponent.find(''button'').simulate(''click''); return waitForIt(() => mockedComponent )}; const afterSubmit_1 = await firstSubmit(); const submitState_1 = afterSubmit_1.state(); const testMessage_2 = ''__SECOND__MESSAGE__''; const secondChange = () => { causeChange(mockedComponent, testMessage_2); return waitForIt(() => mockedComponent )}; const secondResult = await secondChange(); const secondSubmit = () => { mockedComponent.find(''button'').simulate(''click''); return waitForIt(() => mockedComponent )}; const afterSubmit_2 = await secondSubmit(); const submitState_2 = afterSubmit_2.state(); assert(initialState.messages.length === 0 && submitState_1.messages.length === 1 && submitState_2.messages.length === 2 && submitState_2.messages[1] === testMessage_2); }; '
- text: The submitMessage
method should clear the current input.
testString: 'async () => { const mockedComponent = Enzyme.mount(React.createElement(DisplayMessages)); const waitForIt = (fn) => new Promise((resolve, reject) => setTimeout(() => resolve(fn()), 100)); const causeChange = (c, v) => c.find(''input'').simulate(''change'', { target: { value: v }}); const initialState = mockedComponent.state(); const testMessage = ''__FIRST__MESSAGE__''; const firstChange = () => { causeChange(mockedComponent, testMessage); return waitForIt(() => mockedComponent )}; const firstResult = await firstChange(); const firstState = firstResult.state(); const firstSubmit = () => { mockedComponent.find(''button'').simulate(''click''); return waitForIt(() => mockedComponent )}; const afterSubmit = await firstSubmit(); const submitState = afterSubmit.state(); assert(firstState.input === testMessage && submitState.input === ''''); }; '
```