Benchmark: Copying data; mapping vs. spreading then modifying vs. Object.assign then modifiying

Script Preparation code:

var data = [{
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    }
];

Tests:

Mapping
data.map((d, i) => i=== 2 ? "replaced" : d)
spreading, then modifying
const copy = [...data]; copy[2] = "replaced";
Object.assign, then modifying
const copy = Object.assign([], data) copy[2] = "replaced";

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Mapping
spreading, then modifying
Object.assign, then modifying

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:101.0) Gecko/20100101 Firefox/101.0

Browser/OS: Firefox 101 on Linux

View result in a separate tab

Test name	Executions per second
Mapping	16935210.0 Ops/sec
spreading, then modifying	8021250.0 Ops/sec
Object.assign, then modifying	1541070.0 Ops/sec

Copying data; mapping vs. spreading then modifying vs. Object.assign then modifiying (version: 0)

Comparing performance of: Mapping vs spreading, then modifying vs Object.assign, then modifying

Created: one year ago by: Guest

Jump to the latest result

Mapping

spreading, then modifying

Object.assign, then modifying

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A