Use short-circuits conditionals

If you want to execute a function when a condition matches, then use short-circuit to shorten the code:

if (formValid) {
    submitForm();
}

// Use short-circuit
formValid && submitForm();

The logical OR operator `||` is used in a simliar way:

!formValid || submitForm();

In the modern web frameworks, we can use the similar syntax to render a given component when a condition satisfies. The following sample code gives you the idea of conditional rendering in React:

{
    unreadMessages.length > 0 && <div>You have {unreadMessages.length} unread messages.</div>;
}

Use negative nth-child and nth-last-child

Use string literals for the TypeScript enum values