Object.assign vs object spread
JavaScript performance comparison
Preparation code
<script>
Benchmark.prototype.setup = function() {
if (typeof Object.assign != 'function') {
// Must be writable: true, enumerable: false, configurable: true
Object.defineProperty(Object, "assign", {
value: function assign(target, varArgs) { // .length of function is 2
'use strict';
if (target == null) { // TypeError if undefined or null
throw new TypeError('Cannot convert undefined or null to object');
}
var to = Object(target);
for (var index = 1; index < arguments.length; index++) {
var nextSource = arguments[index];
if (nextSource != null) { // Skip over if undefined or null
for (var nextKey in nextSource) {
// Avoid bugs when hasOwnProperty is shadowed
if (Object.prototype.hasOwnProperty.call(nextSource, nextKey)) {
to[nextKey] = nextSource[nextKey];
}
}
}
}
return to;
},
writable: true,
configurable: true
});
}
var x = {};
for (var i = 0; i < 1000000; i += 1) {
x[i] = i;
}
};
</script>
Test runner
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Test | Ops/sec | |
---|---|---|
Object.assign
|
|
pending… |
Spread
|
|
pending… |
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Revisions
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