Benchmark: Repeating String

Tests:

Simple for loop
function repeatify(string, repetitions) { if (repetitions < 0 || repetitions === Infinity) { throw new RangeError('Invalid repetitions number'); } let result = ''; for (let i = 0; i < repetitions; i++) { result += string; } return result; } repeatify('*', 10000);
Extended for loop
function repeatify2(string, repetitions) { if (repetitions < 0 || repetitions === Infinity) { throw new RangeError('Invalid repetitions number'); } const isEven = repetitions % 2 === 0; const iterations = Math.floor(repetitions / 2); const stringTwice = string + string; let result = ''; for (let i = 0; i < iterations; i++) { result += stringTwice; } if (!isEven) { result += string; } return result; } repeatify2('*', 10000);
Log based
function repeatify3(string, repetitions) { if (repetitions < 0 || repetitions === Infinity) { throw new RangeError('Invalid repetitions number'); } const cache = new Map(); function repeat(string, repetitions) { if (repetitions === 0) { return ''; } const log = Math.floor(Math.log2(repetitions)); let result; if (cache.has(log)) { result = cache.get(log); } else { result = string; for (let i = 1; i <= log; i++) { result += result; cache.set(i, result); } } const repetitionsProcessed = Math.pow(2, log); const repetitionsLeft = repetitions - repetitionsProcessed; return result + repeat(string, repetitionsLeft); } return repeat(string, repetitions); } repeatify3('*', 10000);

Rendered benchmark preparation results:

Previous results

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Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 15_3_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.3 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 15 on iOS 15.3.1

Repeating String (version: 0)