UI

classnames

Replacing classnames classnames(a, b, c)

Vanilla JavaScript
const isPrimary = true;
const isError = false;

// Native array filtering
const classList = [
  'button',
  isPrimary && 'primary',
  isError && 'error',
  'rounded'
].filter(Boolean).join(' ');

// output: "button primary rounded"

Why Use This?

Libraries like `classnames` or `clsx` are extremely popular in React loops, but an inline array with `.filter(Boolean).join(' ')` does exactly the same trick natively. It leverages short-circuit `&&` evaluations naturally.