JavaScript Conditional #

if #

if (<condition>) {
    ...;
}

Example:

let some_var = true;

if (some_var) {
    console.log('sup');
}

if-else #

if {<conditional>} {
    ...;
} else {
    ...;
};

Ternary operator #

Super condensation of conditionals.

Goes from:

if (<condition>) {
    <thing1>;
} else {
    <thing2>;
}

to this:

<condition> ? <thing1> : <thing2>;

else-if #

More conditionals. The first that evaluates true executes.

if (<condition1>) {
    ...;
} else if (<condition2>) {
    ...;
} else {
    ...;
}

switch #

A cleaner else if.

switch (<thing to be compared against for equivalence>) { // argument can just be a value
    case <what the argument gets compared against>: // just be a value
        ...; // do something
        break;
    case <another point of comparison>:
        ...;
        break;
    default: // for when nothing is true or matches up
        ...;
        break;
}

break exits code and doesn’t run more.

Comparison #

<
>
<=
=>
=== - equivalent
!== - not equivalent

Boolean #

&& - and
|| - or
! - not

Truthy vs. Falsy #

A variable is truthy if it’s been assigned something not falsy.

What’s falsy? Stuff like:

0
empty strings
null
undefined
NaN

Good for shorthand syntax.

Sidenote: short-circuit evaluation.