Christian Genco


Change the value of a checkbox #

To control an input with type="checkbox" set the value with checked instead of value and get the value from instead of

  onChange={(e) => setChecked(}

Interview questions #

What is JSX? #

Javascript XML (JSX) is syntactic sugar for writing HTML in Javascript files, like this:

return <a href="/hi">hello world</a>;

JSX compiles down to plain ol' Javascript. The above would compile down to something like return React.createElement("a", { href: "/hi" }, "hello world");

React component lifecycle methods #

React lifecycle methods cart

React lifecycle methods cart

The most important lifecycle methods are:

Every React hook #

  1. useState
  2. useEffect
  3. useRef
  4. useMemo
  5. useCallback
  6. useContext
  7. useLayoutEffect
  8. useReducer
  9. useImperativeHandle