Benchmark: Big Array prepend

Script Preparation code:

var a;
var prependArray = function(value, oldArray) {
    var i, len = oldArray.length + 1,
        newArray = new Array(len);
    newArray[0] = value;
    for (i = 0; i < len; ++i) {
        newArray.push(oldArray[i]);
    }
    return newArray;
}

Tests:

Spread Operator
a = new Array(10000).fill().map((_, i) => i) a = [0, ...a];
Unshift
a = new Array(10000).fill().map((_, i) => i) a.unshift(0);
Unshift without mutation
a = new Array(10000).fill().map((_, i) => i) a.slice(0).unshift(0);
Prepend function
a = new Array(10000).fill().map((_, i) => i) prependArray(0, a);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread Operator
Unshift
Unshift without mutation
Prepend function

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36

Browser/OS: Chrome 83 on Mac OS X 10.15.4

View result in a separate tab

Test name	Executions per second
Spread Operator	8107.9 Ops/sec
Unshift	9149.0 Ops/sec
Unshift without mutation	8510.9 Ops/sec
Prepend function	2551.1 Ops/sec

Big Array prepend (version: 0)

Comparing performance of: Spread Operator vs Unshift vs Unshift without mutation vs Prepend function

Created: 3 years ago by: Guest

Jump to the latest result

Spread Operator

Unshift

Unshift without mutation

Prepend function

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A