Run results for: for in or reduce

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser: Chrome 126

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
forInFunc	113987.4 Ops/sec
funcReduce	88627.1 Ops/sec

Script Preparation code:

var testInitialConfig = { key1: 123, key2: [], key3: { a: 123 } };
var testOverrideConfig = { key1: 'abc', key3: { a: [] } };

var funcReduce = (initialConfig, overrideConfig) => {
  if (!overrideConfig) {
    return { ...initialConfig };
  }

  const keys = Object.keys(initialConfig);

  return keys.reduce(
    (acc, key) => {
      if (overrideConfig[key]) {
        return {
          ...acc,
          [key]: {
            ...initialConfig[key],
            ...overrideConfig[key],
          },
        };
      }

      return acc;
    },
    { ...initialConfig },
  );
};

var forInFunc = (initialConfig, overrideConfig) => {
  const mergedConfig = { ...initialConfig };

  if (!overrideConfig) {
    return mergedConfig;
  }

  for (const keyString in initialConfig) {
    const key = keyString;

    if (overrideConfig[key]) {
      mergedConfig[key] = {
        ...initialConfig[key],
        ...overrideConfig[key],
      };
    }
  }

  return mergedConfig;
};

Tests:

forInFunc
const result1 = forInFunc(testInitialConfig, testOverrideConfig) console.log(result1)
funcReduce
const result2 = funcReduce(testInitialConfig, testOverrideConfig) console.log(result2)