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- "use strict";
-
- exports.__esModule = true;
- exports.default = useMergeState;
-
- var _react = require("react");
-
- function _extends() { _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; }; return _extends.apply(this, arguments); }
-
- /**
- * Mimics a React class component's state model, of having a single unified
- * `state` object and an updater that merges updates into the existing state, as
- * opposed to replacing it.
- *
- * ```js
- * const [state, setState] = useMergeState({ name: 'Betsy', age: 24 })
- *
- * setState({ name: 'Johan' }) // { name: 'Johan', age: 24 }
- *
- * setState(state => ({ age: state.age + 10 })) // { name: 'Johan', age: 34 }
- * ```
- *
- * @param initialState The initial state object
- */
- function useMergeState(initialState) {
- var _useState = (0, _react.useState)(initialState),
- state = _useState[0],
- setState = _useState[1];
-
- var updater = (0, _react.useCallback)(function (update) {
- if (update === null) return;
-
- if (typeof update === 'function') {
- setState(function (state) {
- var nextState = update(state);
- return nextState == null ? state : _extends({}, state, {}, nextState);
- });
- } else {
- setState(function (state) {
- return _extends({}, state, {}, update);
- });
- }
- }, [setState]);
- return [state, updater];
- }
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