What will be the value of a? let a = -1 ? 'foo' ? null : -1 : 1; 

What is TypeError?

What's the output? if we call f(3)? const f = (x, y = true) => x * y;

What's true about the document object in any environment?

What will be logged in the console? let a = { [ 'foo_' + (() => 1)() ]: 2 }; console.log(a);

What is the Promise?

Which Array prototype method actually modifies the array it's been called on?

What will be printed to console? function Foo(){ var foo = 1; bar = 'hello' } var f = new Foo; console.log(f.foo,bar);

What is the value of 'x' after the following code runs? var x; x++;

What is the value of c? var a = function(){ this.b = 1; } var b = function(){ this.b = new a().b; return 5; } var c = b() + new b();

What's the output? var test = function (firstName, surname) { this.Name.FirstName = firstName; this.Name.Surname = surname; } test.prototype = { Name: { FirstName: undefined, Surname: undefined } } var b = new test('john', 'doe'); var c = new test('bob', 'templeton'); console.log(b.Name.FirstName + ' ' + b.Name.Surname + ', ' + c.Name.FirstName + ' ' + c.Name.Surname);