test-spread-deopts.js

const N = 10000;

let prev1, prev2, prev3, prev4;
let counter1 = 0, counter2 = 0, counter3 = 0, counter4 = 0;

function test(obj) {
  if (!prev1) {
        prev1 = obj;
  }
  if (!%HaveSameMap(prev1, obj)) {
        counter1++;
  }

  let result = 0;
  for (let i = 0; i < N; i++) {
  	result += obj.a + obj.b
  }
  return result;
}
function test2(obj) {
        if (!prev2) {
                prev2 = obj;
          }
          if (!%HaveSameMap(prev2, obj)) {
                counter2++;
          }
let result = 0;
  for (let i = 0; i < N; i++) {
  	result += obj.a + obj.b
  }
  return result;
}

function test3(obj) {
        if (!prev3) {
                prev3 = obj;
          }
          if (!%HaveSameMap(prev3, obj)) {
                counter3++;
          }
  let result = 0;
  for (let i = 0; i < N; i++) {
        result += obj.a + obj.b
  }
  return result;
}

function test4(obj) {
        if (!prev4) {
                prev4 = obj;
          }
          if (!%HaveSameMap(prev4, obj)) {
                counter4++;
          }
  let result = 0;
  for (let i = 0; i < N; i++) {
        result += obj.a + obj.b
  }
  return result;
}

const objToCopy1 = { a: 1, b: 2 };
const objToCopy2 = { a: 1, b: 2 };
const objToCopy3 = { a: 1, b: 2 };
const objToCopy4 = { a: 1, b: 2 };
const objToCopy5 = { a: 1, b: 2 };
const startParse = Date.now();
for (let i = 0; i < N; ++i) {

	test(JSON.parse(JSON.stringify(objToCopy1)));
	test(JSON.parse(JSON.stringify(objToCopy2)));
	test(JSON.parse(JSON.stringify(objToCopy3)));
	test(JSON.parse(JSON.stringify(objToCopy4)));
	test(JSON.parse(JSON.stringify(objToCopy5)));
}

console.log("test with PARSE:", Date.now() - startParse, "ms.");
console.log(`Optimization status + ${%GetOptimizationStatus(test)}`)

const startStructuredClone = Date.now();
for (let i = 0; i < N; ++i) {
        test2(structuredClone(objToCopy1));
        test2(structuredClone(objToCopy2));
        test2(structuredClone(objToCopy3));
        test2(structuredClone(objToCopy4));
        test2(structuredClone(objToCopy5));
}

console.log("test with structuredClone:", Date.now() - startStructuredClone, "ms.");
console.log(`Optimization status ${%GetOptimizationStatus(test2)}`)

const startSpread = Date.now();
for (let i = 0; i < N; ++i) {
        test3({...objToCopy1});
        test3({...objToCopy2});
        test3({...objToCopy3});
        test3({...objToCopy4});
        test3({...objToCopy5});
}

console.log("test with spread:", Date.now() - startSpread, "ms.");
console.log(`Optimization status ${%GetOptimizationStatus(test3)}`)

const startObjectAssign = Date.now();
for (let i = 0; i < N; ++i) {
        test4(Object.assign({}, objToCopy1));
        test4(Object.assign({}, objToCopy2));
        test4(Object.assign({}, objToCopy3));
        test4(Object.assign({}, objToCopy4));
        test4(Object.assign({}, objToCopy5));
}

console.log("test with ObjectAssign:", Date.now() - startObjectAssign, "ms.");
console.log(`Optimization status ${%GetOptimizationStatus(test4)}`)

console.log(`Deopt counters`);
console.log({counter1, counter2, counter3, counter4})