Run results for: Merge array of objects with an object.

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.5112.81 Safari/537.36

Browser: Chrome 104

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
assign	286686.3 Ops/sec
reduce with spread operator	281647.8 Ops/sec

Script Preparation code:

var obj = { ...[...Array(10).keys()] };
var arrOfObjs = [];
var obj1 = Array(5).fill(0).map((_, idx) => idx + 5).reduce((acc, val) => {  acc[val] = val;
  return acc;
}, {});
var obj2 = Array(5).fill(0).map((_, idx) => idx + 10).reduce((acc, val) => {acc[val] = val;
  return acc;
}, {});
var obj3 = Array(5).fill(0).map((_, idx) => idx + 15).reduce((acc, val) => {  acc[val] = val;
  return acc;
}, {});
var obj4 = Array(5).fill(0).map((_, idx) => idx + 20).reduce((acc, val) => {  acc[val] = val;
  return acc;
}, {});
arrOfObjs.push(obj1, obj2, obj3, obj4);

Tests:

assign
var result = Object.assign(obj, ...arrOfObjs);
reduce with spread operator
var result = arrOfObjs.reduce((acc, val) => ({ ...acc, ...val }), obj);

Run results for: Merge array of objects with an object.

assign

reduce with spread operator