Run results for: Math.pow(2,n) vs Table lookup vs bitwise

Run details:

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Mobile Safari/537.36

Browser: Chrome Mobile 139

Operating system: Android

Device Platform: Mobile

Date tested: one year ago

Benchmark engine: Benchmark.js

bitwise (1 << n)

49.8M/s

Table lookup

18.9M/s

Math.pow

16.6M/s

View exact numbers

Test name	Executions per second
✓ bitwise (1 << n)	49,788,644 Ops/sec
Table lookup	18,919,326 Ops/sec
Math.pow	16,574,829 Ops/sec

Script Preparation code:

var POWERS = [
		1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536,131072,262144,524288,1048576,2097152,4194304,8388608,16777216,33554432
];

Tests:

Table lookup
let cnt = POWERS.length; let x; for(let i =0;i<cnt;i++){ x = POWERS[i]; }
Math.pow
let cnt = POWERS.length; let x; for(let i =0;i<cnt;i++){ x = Math.pow(2,i); }
bitwise (1 << n)
let cnt = POWERS.length; let x; for(let i =0;i<cnt;i++){ x = (1 << i); }

Run results for: Math.pow(2,n) vs Table lookup vs bitwise

Which is faster: Table lookup or Math.pow(2,value) or bitwise operation (1 << value)?

Table lookup

Math.pow

bitwise (1 << n)