If

Run code depending on whether a boolean condition is true or false.

if(true) {
}

The code inside the if block only runs when the condition block is true. You can compare variables to values or variables to variables, for a true condition.

let reward = false;
let perfect = 0;
let myScore = 0;
if (myScore < 10) {
    myScore += 1;
}

if (myScore == perfect) {
    reward = true;
}

Opposite condition: else

If you want some other code to run when the opposite condition is true, you put it in an additional block area called else.

let colorMix = 0;
let favColor = 10;

if (favColor == 10)
{
    colorMix = 7;
} else {
    colorMix = 472;
}

Opposite condition, but check something again: else if

Another conditional action is to add an if to an else for an else if. It works like this:

let reward = false;
let nearPerfect = 0
let perfect = 0
let myScore = 0;
if (myScore < 10) {
    myScore += 1;
}

if (myScore == perfect) {
    reward = true;
} else if (myScore == nearPerfect) {
    reward = true;
}

You might guess that a longer way of saying the same thing is this:

let reward = false;
let nearPerfect = 0;
let perfect = 0;
let myScore = 0;
if (myScore < 10) {
    myScore += 1;
}

if (myScore == perfect) {
    reward = true;
} else {
    if (myScore == nearPerfect) {
        reward = true;
    }
}