Function Scope

Keep a variable local to the function that declares it.

function_scope.js

function compute(base) {
  const local = base + 1;
  return local * 2;
}

const start = ;
const result = compute(start);

console.log("start=" + start);
console.log("result=" + result);

function compute(base) {
  const local = base + 1;
  return local * 2;
}

const start = ;
const result = compute(start);

console.log("start=" + start);
console.log("result=" + result);

function compute(base) {
  const local = base + 1;
  return local * 2;
}

const start = ;
const result = compute(start);

console.log("start=" + start);
console.log("result=" + result);

function-scope A variable declared inside a function is local to that function. Only the returned value escapes; the local stays private.