@superset-ui/core
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JavaScript
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
import { renderHook } from '@testing-library/react-hooks';
import { usePrevious } from './usePrevious';
test('get undefined on the first render when initialValue is not defined', () => {
const hook = renderHook(() => usePrevious('state'));
expect(hook.result.current).toBeUndefined();
});
test('get initial value on the first render when initialValue is defined', () => {
const hook = renderHook(() => usePrevious('state', 'initial'));
expect(hook.result.current).toBe('initial');
});
test('get state value on second render', () => {
const hook = renderHook(() => usePrevious('state', 'initial'));
hook.rerender(() => usePrevious('state'));
expect(hook.result.current).toBe('state');
});
test('get state value on third render', () => {
const hook = renderHook(() => usePrevious('state'));
hook.rerender(() => usePrevious('state'));
hook.rerender(() => usePrevious('state-2'));
expect(hook.result.current).toBe('state');
});
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