array combin

index.js

const a = {
	key: 'openingHours',
	type: 'openingHours',
	placeholder: 'form_opening_hours',
	properties: {
		// name: 'openingHours',
	},
};


console.log(JSON.stringify(a, null, 2));


// const pls = [[ 1, 2, 3 ], [ 3, 4, 5 ], [ 7, 8, 9 ]],

const pls = [];

for (let i = 0; i < 100; i++) {
	const pl = [];
	for (let j = 0; j < 100; j++) {
		pl.push(j);
	}
	pls.push(pl);
}

function test1() {
	const start = new Date(),
		ids = pls.reduce((res = [], pl) => res.concat(pl), []);
	// console.log(ids, ids.length, (new Date() - start));
	console.log('concat', (new Date() - start));
}

function test2() {
	const start = new Date(),
		ids = pls.reduce((res = [], pl) => { res.push(...pl); return res; }, []);
	// console.log(ids, ids.length, (new Date() - start));
	console.log('push', (new Date() - start));
}

function test3() {
	const start = new Date(),
		ids = pls.reduce((res = [], pl) => { res.splice(res.length - 1, 0, ...pl); return res; }, []);
	// console.log(ids, ids.length, (new Date() - start));
	console.log('splice', (new Date() - start));
}

function test4() {
	const start = new Date(),
		ids = pls.reduce((res = [], pl) => [ ...res, ...pl ], []);
	// console.log(ids, ids.length, (new Date() - start));
	console.log('constructor', (new Date() - start));
}

// 1000 * 10000
// test1(); // 28681 ms
// test2(); // 304
// test3(); // 208
// test4(); // 66134 ms

// 1000 * 100
test1(); // 28681 ms
test2(); // 304
test3(); // 208
test4(); // 66134 ms