What does let mean in JavaScript? 

What is true about JavaScript language?

Value of s.size after executing this code? let s = new Set(); s.add('aa').add('bb').add('cc').add('aa').add('bb')

How many operations can be done simultationsly with JavaScript?

Select options which create object type variables:

How often will message 'hey' be logged in console? setInterval(() => {console.log('hey')},1);

Correct syntax for creating a Date object for January 10, 1998?

What is the value of mike after this code is run? function Person(name, age) { this.name = name; this.age = parseInt(age, 10); } var mike = Person('Mike', '25');

String values have a 'length' property. Why is this property not included in a for-in loop over a string object? var prop, str; str = 'example'; /* str.length === 7 */ for ( prop in str) {}

What does Math.random() do?

Which will create a copy of an array such that changes to the old array will not be reflected in the new array?