Run results for: Global vs Local function

Run details:

User agent: Mozilla/5.0 (Linux; Android 11; Redmi Note 8) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.74 Mobile Safari/537.36 EdgA/99.0.1150.55

Browser: Chrome Mobile 99

Operating system: Android

Device Platform: Mobile

Date tested: 2 years ago

Test name	Executions per second
Local Function	65.6 Ops/sec
Global Function	1.0 Ops/sec

Script Preparation code:

var examples = [];
for(let i = 0; i < 100; i++) {
  examples.push({
    attr: "Hello",
  });
}

function innerFn(obj) {
  function hasAttr(obj) {
    return typeof obj === "object" && "attr" in obj;
  }
  if(hasAttr(obj)) return obj.attr + " world!";
  else return null;
}

function hasAttr(obj) {
  return typeof obj === "object" && "attr" in obj;
}

function outerFn(obj) {
  if(hasAttr(obj)) return obj.attr + " world!";
  else return null;
}

Tests:

Local Function
for(const example of examples) { console.log(innerFn(example)); }
Global Function
for(const example of examples) { console.log(outerFn(example)); }

Run results for: Global vs Local function

Local Function

Global Function