Javascript Bootcamp (ePub)

Javascript Bootcamp is a hands-on tutorial, practical self-exam and reference manual for both beginners and pros. The book is a basic to intermediate level course which focuses on teaching the building blocks and key elements of the language. Javascript is popular as a tool for creating many web and mobile apps. Its form and syntax is based on the timeless and venerable C language. Before diving into the book it's strongly recommended that you first take the included JSAT to gauge your current level of proficiency in Javascript. If you obtain a score of 90% or higher in the JSAT exam, you don't really need to take this course.

The Javascript Assessment Test

Time limit: 30 minutes (All answers found at end of book)

Select the best answer for each question.

1. The line or statement below creates a new context.
eval?.("'use strict'; function f(){console.log('hello')}")
a. true
b. false

2. Under non-strict mode, a statement x = 40 performs what action?

a. variable declaration
b. variable assignment
c. variable declaration or assignment
d. variable declaration and assignment
e. none of the above

3. What best describes the type of relationship between the variable named i and the anonymous function in the code below:

var a = [];
for (var i=0; i<5; ++i){
a[i] = function(){
console.log(i);
}
}

a. one-to-one
b. one-to-many
c. many-to-one
d. many-to-many
e. none of the above

4. Which of the options below would solve the script error?

function f(){
this.msg = "hello"
}

f.prototype.greet = function(name){
console.log(`${this.msg}, ${name}`)
} }

const obj = new f()

setTimeout(obj.greet, 1000, "world!")


a. iteration or recursion
b. block or constant variable
c. function wrapper or reference
d. call or apply method
e. none of the above

5. The var keyword creates properties on the window object.

a. true
b. false

6. Every object instance has a prototype property.
a. true
b. false

7. The strict mode is automatically in effect for a given script.
a. true
b. false

8. Using the let keyword creates properties on the global object.
a. true
b. false

9. How many closures or contexts are created in the given script?

var list = [];

f();

list.forEach(fn=>fn());

function f(){
var strings = ["romeo", "sierra", "tango"];
for (let i = 0; i < 3; i++){
list[i] = ()=>console.log(list[i], strings[i]);
}
}


a. 5
b. 9
c. 1