Can you call a function expression before its assignment in JavaScript?

A function declaration is hoisted with its full body, so it can be called before its line. A function expression is assigned to a variable, which is hoisted (undefined with var, TDZ with let/const) but the function body is only assigned at the line.

A function expression with an internal name, like const greet = function sayHi() {}. The internal name is only visible inside the function, useful for recursion and better stack traces. Outside, you use the variable name.

Use declarations for top-level helpers you want callable from anywhere. Use const function expressions (often arrows) for everything else, to enforce declare-before-use and avoid hoisting surprises.