Questioning the function of "let" when declaring a variable

[GoToLoop]

@quark

console.log('aaa', globalThis.hasOwnProperty('aaa'));
console.log('bbb', globalThis.hasOwnProperty('bbb'));
console.log('ccc', globalThis.hasOwnProperty('ccc'));

Shorter alternative syntax using operator in:

console.log('aaa', 'aaa' in globalThis);
console.log('bbb', 'bbb' in globalThis);
console.log('ccc', 'ccc' in globalThis);

Notice though the operator in is less strict than method hasOwnProperty(); but for most cases, they’re interchangeable:

in - JavaScript | MDN

Object.prototype.hasOwnProperty() - JavaScript | MDN