FED Interview
Question 1
let myObject Go 🧙♂️
Code:
- What would be the output? and why?
let myObject = {
foo: "bar",
func: function() {
var self = this;
console.log(this.foo);
console.log(self.foo);
(function() {
console.log(this.foo);
console.log(self.foo);
})();
(() => {
console.log(this.foo);
console.log(self.foo);
})();
}
};
myObject.func();- What is the difference between the functions? When should we use each?
- What is hoisting? How does it help us?
- Is there a way to secure ourselves from hoisting?
Explenation
Code - Explained
let myObject = {
foo: "bar",
func: function() {
var self = this;
console.log(this.foo);
console.log(self.foo);
(function() {
console.log(this.foo);
console.log(self.foo);
})();
(() => {
console.log(this.foo);
console.log(self.foo);
})();
}
};
myObject.func();Question 2
😴
Let's Implement a sleep function
Hint
/*
* We want some function that would have the signiture below.
* So that when called upon, execution would stop for "ms"amount
*/
function sleep(ms) {
// ...
}Examples
Different Implemetations
- Answer 1
- Bullet Two
- Bullet Three
Explanations
Question 3
Subtitle
Code:
for (var i = 0; i < 5; i++) {
var btn = document.createElement('button');
btn.appendChild(document.createTextNode('Button ' + i));
btn.addEventListener('click', function(){ console.log(i); });
document.body.appendChild(btn);
}What will we see on screen?
What will be the output when clicking on button 2?
How can we fix it?
Solution
Code:
for (var i = 0; i < 5; i++) {
var btn = document.createElement('button');
btn.appendChild(document.createTextNode('Button ' + i));
btn.addEventListener('click', function(){ console.log(i); });
document.body.appendChild(btn);
}What will we see on screen?
What will be the output when clicking on button 2?
How can we fix it?
5 Buttons - each labeled sequentially 1,2,3...
"5" - actually each button would give the same result - "5"
the "bug" is hidden in the "for (var = 0 ....)
var is hoisted - and the "console.log(i);" takes the last value in the hoisted "i"
FED Interview
By Amir Gal-Or
FED Interview
- 136
