Function constructor: new Function() and Function()

Using new Function() creates a new function

WHEN using new Function() THEN this is equivalent to Function() with the same parameters

const fn1 = new Function('a', 'b', 'return a + b'); const fn2 = Function('a', 'b', 'return a + b'); assert.deepStrictEqual(Object.getOwnPropertyDescriptors(fn1), Object.getOwnPropertyDescriptors(fn2));

num params

const fn = new Function('a, b', 'c', 'return null'); assert.strictEqual(fn.length, 3);

Links

spec docs The very first version of the spec defines this property already, the ES1 spec, see section 15.3.2.1 (PDF 732kB).
mdn docs The MDN pages describing this property, easy to read with examples.