Run results for: Spread it and Assign Again

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:101.0) Gecko/20100101 Firefox/101.0

Browser: Firefox 101

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
map	3172990.0 Ops/sec
empty assign	3025670.0 Ops/sec
data assign	3326223.0 Ops/sec
in place mod	10112900.0 Ops/sec

Script Preparation code:

var data = {
  'one': [{
        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"
            }
        }
    }
], 'two': [{
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
          replace: "yes",
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    },
    {
        foo: {
            bar: {
                baz: "hi"
            }
        }
    }
]
};

Tests:

map
let f = { ...data, two: data.two.map((item) => { item.foo.replace == "yes" ? { ...item, something: { n: 234, b: 234 } } : item }), };
empty assign
let o = Object.assign({}, data, { two: data.two.map((item) => { item.foo.replace == "yes" ? { ...item, something: { n: 234, b: 234 } } : item }) })
data assign
let o = Object.assign(data, { two: data.two.map((item) => item.foo.replace == "yes" ? { ...item, something: { n: 234, b: 234 } } : item ) });
in place mod
let f = data.two.find((item) => item.foo.replace == "yes"); f.n = 234; f.b = 234; data

Run results for: Spread it and Assign Again

map

empty assign

data assign

in place mod