jiti-meet/react/features/base/redux/functions.js

139 lines
4.8 KiB
JavaScript

// @flow
import _ from 'lodash';
/**
* Sets specific properties of a specific state to specific values and prevents
* unnecessary state changes.
*
* @param {Object} target - The state on which the specified properties are to
* be set.
* @param {Object} source - The map of properties to values which are to be set
* on the specified target.
* @returns {Object} 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: Object, source: Object) {
let t = target;
for (const property in source) { // eslint-disable-line guard-for-in
t = _set(t, property, source[property], t === target);
}
return t;
}
/**
* 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 {Object} 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 {Object} The specified {@code state} if the value of the specified
* {@code property} equals the specified <tt>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: Object, property: string, value: any) {
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 {Object} 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 {Object} The specified {@code state} if the value of the specified
* {@code property} equals the specified <tt>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: Object,
property: string,
value: any,
copyOnWrite: boolean) {
// 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|Object} 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 | Object) {
if (stateful) {
if (typeof stateful === 'function') {
return stateful();
}
const { getState } = stateful;
if (typeof getState === 'function') {
return getState();
}
}
return stateful;
}