JavaScript, web development questions with actual answers.

JavaScript, web development questions
with actual answers.
programming ANS -the process of taking a problem stated in plain language and writing a set of
instructions to handle the problem (algorithm) in terms your computer can understand (programming
language)



program ANS -a set of instructions for a computer to carry out



algorithm ANS -a step-by-step procedure for solving a problem



jQuery ANS -Popular 3rd party Javascript library



const ANS -Prefix keyword to make a variable constant, you can't change its value



let ANS -Prefix keyword to make a variable that you CAN (but don't need to) change its value

* can be declared without initially setting a value (example=> let myVar;



var ANS -an older way to declare a variable, used in legacy code, differs from `let` slightly when it comes
to variable scope



null ANS -data type that represents a variable with no assigned value



undefined ANS -data type that hasn't been assigned a value. You wouldn't want to purposefully assign
`undefined` as a value but you can always to see if a variable is (or is not)



data types ANS --string(letters/words/unicode characters)

-number (whole or decimal numbers)

-boolean (true/false)

-null (no assigned value)

,-undefined (don't assign this type)

-functions (not technically a data type)

-objects (complex data type--combines primitive data types)



coercion ANS -JS "forcing" a data type to match that of another when you use an operator such as `+`.

EXAMPLE:

const stringVar = 'Kilroy was here ';

const numVar = 12;



const combined = stringVar + numVar;

typeof combined; // => string

console.log(combined); // => Kilroy was here 12



hoisting ANS -JavaScript engine sets up memory for variables and functions that you have made. It is a
way browsers reads through JS...first from top to bottom it identifies all variables and declares space for
them THEN it goes through and executes commands (like functions)



DOM ANS -*the way developers can manipulate webpages using JS



function call sign ANS -( ) .... refers to the arguments or parameters — if any — that get passed to a
function



determinate ANS -In regards to FUNCTIONS...Given the same inputs on separate invocations, the result
should be exactly the same.



function declaration ANS -function myFunction() {

console.log("myFunction");

}



function expression ANS -const myFunction = function(arg1, arg2) {

, console.log("myFunction");

};



**this is a valid way to create a function and some development teams MAY prefer this way



arrow functions ANS -=>

const add = (num1, num2) => num1 + num2;

add(2, 3) // => 5;



// same as above...just uses function keyword

instead of arrow

const addAlt = function(num1, num2) {

return num1 + num2;

}



function ANS -* a block of instructions that can be called on in

code

* a little "machine" that does a specific thing



quotation mark delimiter ANS -'\' --- use the backslash to escape the quotation

mark delimiter

EXAMPLE: const talkSome = "I said \"hi there\"";



* `\` is also used to break long strings into

separate lines



string methods ANS -some examples are:

const fooBar = 'foo bar foo bar';

fooBar.length; // => 15