ES6 Basic
Constants are block-scoped variables.
The statement "let" declares a block scope local variable.
What is the final value of "obj" in the following example?
obj.bar = 2;
What will the result of the following be?
Rest is a new way for functions to handle an arbitrary number of parameters. Can you guess what the mysterious "a" variable holds?
return params;
}
let a = mystery(1,23,4);
String interpolation is a much-needed new feature that is finally available in JavaScript. See the example below. Is there anything wrong with it?
let occupation = 'wizard';
console.log(`Hi! My name is ${name}. I'm a ${occupation}.`);
What value will this expression return?
What will this function return?
let f = this ? class g { } : class h { };
return [ typeof f, typeof h ];
})();
What is a Promise()?
What value will this expression return?
What will the result of this expression be?
What will this function return?
if (false) {
let f = { g() => 1 };
}
return typeof f;
})()
What result will this expression have?
Why is super used?
ES6 introduces a special "const" declaration. Do you know what it does?
console.log(PI) //Prints 3.14
ES6 gives you a number of new methods for operating with Strings. Which one replaces this annoying piece of code?
if(some_text.indexOf('str') !=-1){
return true;
}
Array.from() is a powerful method which converts array-like objects into real Arrays. Why do you use it in the code below?
ES6 gives an alternative way to assign variables. Can you guess what the below code does?
[a, b] = [b, a];
What is stored in the triangle array?
Is this a valid code?
const slave = Slave();
