Coding Questions

Question: What is the value of foo?

var foo = 10 + '20';

Question: What will be the output of the code below?

console.log(0.1 + 0.2 == 0.3);

Question: How would you make this work?

add(2, 5); // 7
add(2)(5); // 7

Question: What value is returned from the following statement?

"i'm a lasagna hog".split("").reverse().join("");

Question: What is the value of window.foo?

( window.foo || ( window.foo = "bar" ) );

Question: What is the outcome of the two alerts below?

var foo = "Hello";
(function() {
var bar = " World";
alert(foo + bar);
})();
alert(foo + bar);

Question: What is the value of foo.length?

var foo = [];
foo.push(1);
foo.push(2);

Question: What is the value of foo.x?

var foo = {n: 1};
var bar = foo;
foo.x = foo = {n: 2};

Question: What does the following code print?

console.log('one');
setTimeout(function() {
console.log('two');
}, 0);
Promise.resolve().then(function() {
console.log('three');
})
console.log('four');

Question: What is the difference between these four promises?

doSomething().then(function () {
return doSomethingElse();
});

doSomething().then(function () {
doSomethingElse();
});

doSomething().then(doSomethingElse());

doSomething().then(doSomethingElse);