Javascript Flashcards

Question

Describe array literal notation.

Answer 1

[ ]; Square brackets with values separated by commas

Answer 2

They are numbered, so easier to organize and recall via their number Adding items to arrays uses push operator whereas objects use the assignment operator Arrays have length properties whereas objects do not.

Answer 3

0 This is why it’s how many spaces to move to get to the value. To get to the first value, you don’t have to move any space. To get to the second value, you move 1 space.

Answer 4

Calculates the number of properties in the array Do not have to calculate on our own

Answer 5

The length of the array - 1

Answer 6

They allow you to package up code for use later in your program It’s a list of steps of a process that can be repeated. They are a special kind of object that is “callable” and reusable

Answer 7

Function keyword An optional name Zero or more parameters A code block An optional return statement

Answer 8

Function name () with 0 or more arguments

Answer 9

Function definition sets up the code for what should be passed and how it should be passed, Keyword and code block in curly braces Function call is when an argument is passed through the function definition set up prior Keyword and argument in parenthesis

Answer 10

Parameter is the definition of what the function will use to pass Parameter is a placeholder for future values Arguments are the value (which take the place of parameters) of what the function will use to pass Parameter and arguments come together to make a variable to make the function happen

Answer 11

The parameters act as the variable of which the function can be called numerous times with different or similar results rather than resulting in only 1 result. Parameters allow us to use a single tool to create variants for our code for the code to be able to do something different

Answer 12

The return statement can cause the function to produce a value. It also exits the function, so no code after the return statement is executed

Answer 13

To see the state of things, it gives a way for us to talk to javascript

Answer 14

Method is a function stored into a property of an object.

Answer 15

A method is not a free floating function. They have be provided context of where they are going to be doing the action Must state object.

Answer 16

pop() method

Answer 17

Math.floor() method

Answer 18

Math.random() method Creates a number somewhere between 0 - 1 (not including 1) Supposed to be a % which is used to multiply by other numbers, where you actually get the randomized numbers between the number provided

Answer 19

splice( start, how many, optional what to add ) method

Answer 20

push() method (add to the end)

Answer 21

split() method and splits it at the argument that is passed. That’s why when we passed a space character(‘ ‘) as an argument, it split at the space acting like a chopping knife splitting

Answer 22

No. We can double check by console.log to see if the original is still there.

Answer 23

50(?) A LOT

Answer 24

Not always. pop() can return what you just took off at the end, but you’re taking it off because you want to remove it from the array. But if you wanted to remove it and then use it elsewhere, then you can return it somewhere else.

Answer 25

<, >, <=, >=, ===, !===

Answer 26

Being able to branching actions and making decisions Checking if something is present or not

Answer 27

If (condition) { code block }

Answer 28

Use the logical operators &&, || in between the condition

Answer 29

Loops can run the same function numerous times until it returns false. Helps do multiple codes in shorter code instead of having to write out every transaction

Answer 30

This limits how many times the loop will run

Answer 31

It’s when the code will be run again from the beginning to end

Answer 32

Before each pass through the loop

Answer 33

Once before the loop begins

Answer 34

Before each loop iteration , at which if evaluates to true, the statement is executed. If false, it exits the loop and goes to the first statement after the for construct.

Answer 35

At the end of each loop iteration, before the next evaluation of condition expression

Answer 36

It increases by 1 Means +1

Answer 37

Use the for… in loop For (var key in object) { statement }

Answer 38

JavaScript Object Notation

Answer 39

Serialization is converting an object to a string (stream of bytes) Deserialization is converting a string (stream of bytes) to the native object (array, object, etc)

Answer 40

This is useful when you want to transmit data across a network or web applications It converts the object in memory into a stream of bytes that can easily be stored on a disk or sent over a network and vice versa Strings are understood in all languages, so it makes the data easily transmittable

Answer 41

JSON.stringify(object);

Answer 42

JSON.parse(string);

Answer 43

storage.setItem(keyName, keyValue); keyName (variable name, kebob case like ‘shopping-cart-case’) should be a string keyValue should also be a string

Answer 44

storage.getItem(keyName); keyName should be a string

Answer 45

Strings only So objects, arrays must all be stringify to strings

Answer 46

Right when the tab/window is about to close and then reload, includes refreshing