Run results for: Empty an array in JavaScript (with baseline) - MeasureThat.net

Run results for: Empty an array in JavaScript (with baseline)

Given an array of 100,000 random numbers, is it faster to empty the array by instantiating a new array, setting its length to zero, splicing it at index zero, or popping all values?

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Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/115.0

Browser: Firefox 115

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Instantiate new array	107.8 Ops/sec
Set length to zero	109.3 Ops/sec
Splice at index zero	113.7 Ops/sec
Pop all values	115.0 Ops/sec
JSON.parse baseline	119.6 Ops/sec

Script Preparation code:

var size = 100000;
var a = [];
for (var i = 0; i < size; i++){
  a.push(Math.random());
}
var json = JSON.stringify(a);

Tests:

Instantiate new array
var a1 = JSON.parse(json); a1 = [];
Set length to zero
var a2 = JSON.parse(json); a2.length = 0;
Splice at index zero
var a3 = JSON.parse(json); a3.splice(0, a3.length);
Pop all values
var a4 = JSON.parse(json); while(a4.length > 0){ a4.pop(); }
JSON.parse baseline
var a0 = JSON.parse(json);