insert to document collection with unique ids

insert.jsx

/**
 * Insert documents to a document collection with unique ids. Override if exists.
 * @param {array} state
 * @param {array} newState
 * @param {string} id
 */
function insert(state, newState, id) {
	let ids = newState.reduce((ids, item) => ({ ...ids, [item[id]]: true }), {});
	return [...state.filter(item => !ids[item[id]]), ...newState];
}