JavaScript

Question 1

Syntax: function

Answer 1

function functionName(params) {

};

Question 2

Syntax: print “Hello”

Answer 2

console.log(“Hello”)

Question 3

what does the var keyword do?

Answer 3

creates a variable in current scope

Question 4

Syntax: random number

Answer 4

Math.random() == 0-1

Question 5

Syntax: for loop

Answer 5

for (var counter = 1; counter < 6; counter++) {  
;
}

Question 6

Syntax: add to end of an array

Answer 6

array.push(‘end’);

Question 7

Syntax: while loop

Answer 7

while (true){
;
}

Question 8

== vs ===

Answer 8

=== is faster, because == does type conversions

Question 9

Syntax: do/while

Answer 9

do {
;
} while (condition);

Question 10

Math.floor()

Answer 10

rounds a number down to its nearest integer

Question 11

Syntax: If/else if/else

Answer 11

if () {
} else if () {
} else {
}

Question 12

isNaN()

Answer 12

returns true if arg is not a number, false if it is

Question 13

Syntax: switch

Answer 13

switch(val_to_check){
    case 'string':
        ;
        break;
    default:
        ;
}

Question 14

Syntax: constructing an instance of an object

Answer 14

var myObj = new Object();

Question 15

Syntax: Object constructor

Answer 15

function myObj(args) {
    this.args = args;
    this.myFunction = function() {
    };
}

Question 16

Syntax: for/in loop

Answer 16

for (var x in object) {
;
}

Question 17

Method vs function

Answer 17

method is a function associated with a certain object

Question 18

Literal constructor vs Constructor notation

Answer 18

obj = {property:value, property:value}
vs
function obj(property1, property2) {this.property1 = property1; this.property2 = property2;}

Question 19

Syntax: determine type of Obj

Answer 19

typeof Obj

Question 20

Syntax: determine whether an Obj has a property

Answer 20

Obj.hasOwnProperty(‘name’)

Question 21

Syntax: add a property or method to a class (and every instance of that class)

Answer 21

Class.prototype.property_or_method

Question 22

Syntax: Class inherits from Parent

Answer 22

Child.prototype = new Parent();

Question 23

Syntax: Making a variable private

Answer 23

In class declaration, instead of “this.name = name;” use “var name = name”