38 lines
1.4 KiB
JavaScript
38 lines
1.4 KiB
JavaScript
/**
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* Sets a specific property of a specific state to a specific value. Prevents
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* unnecessary state changes (when the specified <tt>value</tt> is equal to the
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* value of the specified <tt>property</tt> of the specified <tt>state</tt>).
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*
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* @param {Object} state - The (Redux) state from which a new state is to be
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* constructed by setting the specified <tt>property</tt> to the specified
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* <tt>value</tt>.
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* @param {string} property - The property of <tt>state</tt> which is to be
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* assigned the specified <tt>value</tt> (in the new state).
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* @param {*} value - The value to assign to the specified <tt>property</tt>.
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* @returns {Object} The specified <tt>state</tt> if the value of the specified
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* <tt>property</tt> equals the specified <tt>value/tt>; otherwise, a new state
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* constructed from the specified <tt>state</tt> by setting the specified
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* <tt>property</tt> to the specified <tt>value</tt>.
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*/
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export function setStateProperty(state, property, value) {
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// Delete state properties that are to be set to undefined. (It is a matter
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// of personal preference, mostly.)
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if (typeof value === 'undefined'
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&& Object.prototype.hasOwnProperty.call(state, property)) {
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const newState = { ...state };
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if (delete newState[property]) {
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return newState;
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}
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}
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if (state[property] !== value) {
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return {
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...state,
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[property]: value
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};
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}
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return state;
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}
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