Run results for: Array initialization: preallocate vs push vs preallocate & fill

Run details:

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0

Browser: Firefox 132

Operating system: Ubuntu

Device Platform: Desktop

Date tested: one year ago

Preallocate

62K/s

Push

52K/s

Index

45K/s

Preallocate & fill

41K/s

View exact numbers

Tests:

Preallocate
var N = 10000; var result = new Array(N); for (var i = 0; i < N; i++) { result[i] = i * 2; }
Preallocate & fill
var N = 10000; var result = new Array(N).fill(0); for (var i = 0; i < N; i++) { result[i] = i * 2; }
Push
var N = 10000; var result = []; for (var i = 0; i < N; i++) { result.push(i * 2); }
Index
var N = 10000; var result = []; for (var i = 0; i < N; i++) { result[i] = i * 2; }