closures.md

Closures

Closure is created when an inner function has access to its outer function variables and arguments. The inner function has access to –

1. Its own variables.
2. Outer function's variables and arguments.
3. Global variables.

function wrapValue(n) {
  let local = n;
  return (m) => local * m;  // returns a function, not an evaluation of n * m
}

let wrap1 = wrapValue(1);
let wrap2 = wrapValue(2);
console.log(wrap1(3))  // calls function returned by wrapValue(); → 3
console.log(wrap2(4))  // calls function returned by wrapValue(); → 8

Sources

• https://eloquentjavascript.net/03_functions.html#h_hOd+yVxaku
• https://www.freecodecamp.org/news/javascript-closure-tutorial-with-js-closure-example-code/