Week 1 Flashcards

Question

What are the primitive javascript data types?

Answer 1

Number: This data type is used to represent both integer and floating-point numbers. String: This data type is used to store text or a sequence of characters. We use single quotes, double quotes, or backticks to denote a string. Boolean: This data type represents logical values. It can only be `true` or `false`. Null: This data type represents the intentional absence of any object value. It has only one value: `null`. Undefined: This data type is assigned to a variable that has been declared but has not been assigned a value.

Answer 2

typeof ex. let age = 30; console.log(typeof age);

Answer 3

A function is a way to write reusable code. This code lives in one place and you can use it elsewhere as many times as you like.

Answer 4

A parameter list is a local variable named after whatever if put in the ( ) of the function. E.x function sayWord(Word){ alert(word) } Word is a variable that is declared without let or const. It only exists inside the function and its automatically deleted when the function ends.

Answer 5

The variable is created inside the function and its localized to that function only and cannot be referenced outside of it

Answer 6

It means that you are passing an argument (value) to a function. When a function is called, the variables declared inside the function from the parameter list receive their values from the function call's argument list. function sayWord(Word){ alert(word); } sayWord('rutabaga'); the above line is passing the sayWord function an argument of 'rutabaga' and this is where (word) gets its value.

Answer 7

The number of arguments you can pass to a function is based on the number of declarations in the function. ex. function getArea(width,height){ alert(width * height); } The above function needs 2 arguments to run. The function has 2 declarations so 2 arguments can be passed like the example below. getArea(8,9);

Answer 8

Functions always returns a single value. if you do not provide that value, it returns undefined. when you use return in a function you can use that returned value in your code to continue working on it. Ex. function getArea(width,height){ return width * height; } let area = getArea(3,4); alert(area); Above we are returning the area of 2 arguments and assigning it to the variable called area and using it on the next line to fire an alert.

Answer 9

The value is returned to where the function was called in your code and following that line you will be able to use it. Ex. function getArea(width,height){ return width * height; } let area = getArea(3,4); alert(area); above alert(area); was able to access this immediately below the line that called the function. If this alert was above it it would not have a value.

Answer 10

=== will not handle implicit type conversion == will handle implicit type conversion. ex. 5==='5' will evaluate to false 5=='5' will evaluate to true the implicit type conversion is done by Javascript and its able to make a agreeable assumption that this string does contain a number and when converted to a number it does equal 5.

Answer 11

null === undefined , false null == undefined, true

Answer 12

false null undefined empty string NaN 0

Answer 13

&& tests if the left operand is truthy or falsy. If falsy then it will return the left operands value and if its thruthy then it returns the right operand. If both operands are truthy it returns the last truthy value.

Week 1 Flashcards

(38 cards)