Run results for: Closure overhead vs function overhead vs inline

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36

Browser: Chrome 110

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Inline	1.6 Ops/sec
IIFE	1.6 Ops/sec
External function	9.0 Ops/sec

Script Preparation code:

var NUM_ITERATIONS = 1000000

var state = [987654321, 987654321, 987654321, 987654321];


var baz_inner = (state) => {
    state[0] = ((state[0] & 0xFFFFFFFE) << 18) ^ (((state[0] << 6) ^ state[0]) >> 13);
    state[1] = ((state[1] & 0xFFFFFFF8) << 2) ^ (((state[1] << 2) ^ state[1]) >> 27);
    state[2] = ((state[2] & 0xFFFFFFF0) << 7) ^ (((state[2] << 13) ^ state[2]) >> 21);
    state[3] = ((state[3] & 0xFFFFFF80) << 13) ^ (((state[3] << 3) ^ state[3]) >> 12);
}

Tests:

Inline
state = [987654321, 987654321, 987654321, 987654321]; for (let i = 0; i < NUM_ITERATIONS; i++) { state[0] = ((state[0] & 0xFFFFFFFE) << 18) ^ (((state[0] << 6) ^ state[0]) >> 13); state[1] = ((state[1] & 0xFFFFFFF8) << 2) ^ (((state[1] << 2) ^ state[1]) >> 27); state[2] = ((state[2] & 0xFFFFFFF0) << 7) ^ (((state[2] << 13) ^ state[2]) >> 21); state[3] = ((state[3] & 0xFFFFFF80) << 13) ^ (((state[3] << 3) ^ state[3]) >> 12); }
IIFE
state = [987654321, 987654321, 987654321, 987654321]; for (let i = 0; i < NUM_ITERATIONS; i++) { (() => { state[0] = ((state[0] & 0xFFFFFFFE) << 18) ^ (((state[0] << 6) ^ state[0]) >> 13); state[1] = ((state[1] & 0xFFFFFFF8) << 2) ^ (((state[1] << 2) ^ state[1]) >> 27); state[2] = ((state[2] & 0xFFFFFFF0) << 7) ^ (((state[2] << 13) ^ state[2]) >> 21); state[3] = ((state[3] & 0xFFFFFF80) << 13) ^ (((state[3] << 3) ^ state[3]) >> 12); })(); }
External function
state = [987654321, 987654321, 987654321, 987654321]; for (let i = 0; i < NUM_ITERATIONS; i++) { baz_inner(state); }

Run results for: Closure overhead vs function overhead vs inline

Runs a pseudo random number generator in a loop. To determine overhead from IIFE in a loop versus function call overhead

Inline

IIFE

External function