Basic Programming Cheat Sheet by tegdsd12

the value assigned can be referenced in later parts of the program through variab­leName.
Only one value can be assigned to one variable, i.e one instan­tiation per variable, if let var1 = 'string' previo­usly, cannot let var1 = 2 again later in the code

- initia­lized with square brackets
- can contain all data types, including arrays and objects
- ordered list of values, starting from index 0 to refer to first element
- get item in array by referring to its index (array[0] gets 'string', array[1] gets 2)

similar to array, but replace index with key(st­ring)
can contain all data types, including arrays and objects
refer to objects in 2 ways
1. object.key1 gets value1
2. object­['k­ey2'] gets value2. when using square brackets, put the key in string format

let num1 = 1;
let num2 = 20;
let result = addTog­eth­er(­num1, num2);

num1 and num2 becomes firstNum and secondNum respec­tively
if no return value, calcul­ations done in the function cannot be carried out of the function

function addTog­eth­er(­fir­stNum, secondNum) {
return firstNum + secondNum;
}

result will get the returned value of 21

loop (condi­tion) {
execute code in block
}

for

for has multiple uses
1.a condensed while loop
for (let i = 0; i< 10; i++) {}
2. To loop through an array/­object
let numbers = [20, 30, 10, 50, 70];
for (let number of numbers) {
use value
each loop uses number = 20, then 30, 10 ...
}
for (let numbers in numbers) {
use index/key
each loop uses number = 0, then 1, 2 ...
to get value, use number­s[n­umber] (objec­t[i­ndex])
}

functions are called with brackets -> foo()
if function has parame­ters, function must be called with parameters -> foo(param)
parameters are assigned to new names for usage in the function (see below)