import _ from 'lodash'; import { connect as reduxConnect } from 'react-redux'; import { IStore } from '../../app/types'; /** * Sets specific properties of a specific state to specific values and prevents * unnecessary state changes. * * @param {T} target - The state on which the specified properties are to * be set. * @param {T} source - The map of properties to values which are to be set * on the specified target. * @returns {T} The specified target if the values of the specified * properties equal the specified values; otherwise, a new state constructed * from the specified target by setting the specified properties to the * specified values. */ export function assign(target: T, source: T): T { let t = target; for (const property in source) { // eslint-disable-line guard-for-in t = _set(t, property, source[property], t === target); } return t; } /** * Wrapper function for the react-redux connect function to avoid having to * declare function types for flow, but still let flow warn for other errors. * * @param {any} mapStateToProps - Redux mapStateToProps function. * @param {Function?} mapDispatchToProps - Redux mapDispatchToProps function. * @returns {Connector} */ export function connect( mapStateToProps?: any, mapDispatchToProps?: Function) { return reduxConnect(mapStateToProps, mapDispatchToProps); } /** * Determines whether {@code a} equals {@code b} according to deep comparison * (which makes sense for Redux and its state definition). * * @param {*} a - The value to compare to {@code b}. * @param {*} b - The value to compare to {@code a}. * @returns {boolean} True if {@code a} equals {@code b} (according to deep * comparison); false, otherwise. */ export function equals(a: any, b: any) { return _.isEqual(a, b); } /** * Sets a specific property of a specific state to a specific value. Prevents * unnecessary state changes (when the specified {@code value} is equal to the * value of the specified {@code property} of the specified {@code state}). * * @param {T} state - The (Redux) state from which a new state is to be * constructed by setting the specified {@code property} to the specified * {@code value}. * @param {string} property - The property of {@code state} which is to be * assigned the specified {@code value} (in the new state). * @param {*} value - The value to assign to the specified {@code property}. * @returns {T} The specified {@code state} if the value of the specified * {@code property} equals the specified value/tt>; otherwise, a new state * constructed from the specified {@code state} by setting the specified * {@code property} to the specified {@code value}. */ export function set(state: T, property: keyof T, value: any): T { return _set(state, property, value, /* copyOnWrite */ true); } /* eslint-disable max-params */ /** * Sets a specific property of a specific state to a specific value. Prevents * unnecessary state changes (when the specified {@code value} is equal to the * value of the specified {@code property} of the specified {@code state}). * * @param {T} state - The (Redux) state from which a state is to be * constructed by setting the specified {@code property} to the specified * {@code value}. * @param {string} property - The property of {@code state} which is to be * assigned the specified {@code value}. * @param {*} value - The value to assign to the specified {@code property}. * @param {boolean} copyOnWrite - If the specified {@code state} is to not be * modified, {@code true}; otherwise, {@code false}. * @returns {T} The specified {@code state} if the value of the specified * {@code property} equals the specified value/tt> or {@code copyOnWrite} * is truthy; otherwise, a new state constructed from the specified * {@code state} by setting the specified {@code property} to the specified * {@code value}. */ function _set( state: T, property: keyof T, value: any, copyOnWrite: boolean): T { // Delete state properties that are to be set to undefined. (It is a matter // of personal preference, mostly.) if (typeof value === 'undefined' && Object.prototype.hasOwnProperty.call(state, property)) { const newState = copyOnWrite ? { ...state } : state; if (delete newState[property]) { return newState; } } if (state[property] !== value) { if (copyOnWrite) { return { ...state, [property]: value }; } state[property] = value; } return state; } /* eslint-enable max-params */ /** * Returns redux state from the specified {@code stateful} which is presumed to * be related to the redux state (e.g. The redux store, the redux * {@code getState} function). * * @param {Function|IStore} stateful - The entity such as the redux store or the * redux {@code getState} function from which the redux state is to be * returned. * @returns {Object} The redux state. */ export function toState(stateful: Function | IStore) { if (stateful) { if (typeof stateful === 'function') { return stateful(); } const { getState } = stateful; if (typeof getState === 'function') { return getState(); } } return stateful; }