Core Javascript coding test

// call , apply, bind
//1. How to use bind() feature in javascript with example
let button = function(content) {
this.content = content;
};

button.prototype.click = function() {
console.log(`${this.content} clicked `);
};

let newbtn = new button('add');

let boundclick = newbtn.click.bind(newbtn);
boundclick();

//2. bind() using async funs
let myobj = {
asyncGet(cb) {
cb();
},
parse() {
console.log('parse called');
},
render() {
this.asyncGet(function() {
this.parse();
}.bind(this))
}
};
myobj.render();


// ----------------------------JS Coding Test------------------------------------
//1. What does the following statement declares?
var myArray = [
[
[]
]
];
// A. 3 dimension array

//2.Question: What value is returned from the above statement?
var test = "i'm a lasagna hog".split("").reverse().join("");
//Answer: "goh angasal a m'i"

//3. What is returned ? 
(function(x) {
delete x;
return x;
})(1);

//4. Question: What is the outcome of the two alerts above?
var foo = "Hello";
(function() {
var bar = " World";
alert(foo + bar);
})();
alert(foo + bar);
// Answer: "Hello World" & ReferenceError: bar is not defined


//5. What is the value of foo.length?
var ninja = {};
ninja.bar = 'hello';
// Answer: undefined

//6. what is the value of "x"?
var y = 1,
x = y = typeof x;
x;


//7.Consider the two functions below. Will they both return the same thing? Why or why not?
function foo1() {
return {
bar: "hello"
};
}

function foo2() {
return {
bar: "hello"
};
}

//8. Will JavaScript function allow arbitrary number of arguments? Print console by reading arguments.
sum(2, 3);
sum(1, 2, 3, 4);
//Answer.
function sum() {
for (var i = 0; i < arguments.length; i++) {
console.log(arguments[i]);
}
}

//9. what is the printed in ES5?
function calculateTotalAmount(vip) {
var amount = 0
if (vip) {
var amount = 1
} { // more crazy blocks!
var amount = 100 {
var amount = 1000
}
}
return amount
}

console.log(calculateTotalAmount(true));

//10. Using ES6, refactor this code to perform Parallel tasks(without error handling)?
//sequential tasks (without error handling)
function getTotalFileSize(file1, file2, fil3, callback) {
let total = 0;
stat(file1(error, info) => {
total += info.size;
stat(file2(error, info) => {
total += info.size;
stat(file3(error, info) => {
total += info.size;
callback(total);
});
});
});
}

//11. Does this code work?
function hello(track) {
if (track === 'skill') {
action = 'dance';
} else {
action = 'skip';
}
var action;

return action;
}

//12. Explain why the following doesn't work as an IIFE: Immediately invoked function expression. will there be any error in the code?
function foo(){
// your logic here
}();

// Ans: functions as expressions vs definitions.
// To fix this bug, write like:
( function foo() {}) ();