How does nested functions work in javascript? Any examples?

Question

Nested functions in javascript

Answer 1

Nested functions are simply functions in a function. You declare them inside a function block.

function total(array) {
function isNumber(o) {
return typeof o === "number";
}

var sum = 0;
for (var i = 0; i < array.length; i++) {
if (isNumber(array[i]) {
sum += array[i];
}
}
return sum;
}

total([5, 7, "6", 2]); // returns 14

Here `isNumber` is nested inside the function `total`.