JS: let or var

let_or_var.js

// The difference is scoping. var is scoped to the nearest function block and let is scoped to the nearest enclosing block 
// (both are global if outside any block), which can be smaller than a function block.

// Also, variables declared with let are not visible before they are declared in their enclosing block.

// In the example below, let is only visible in the for() loop and var is visible to the whole function.

function allyIlliterate() {
    //tuce is *not* visible out here

    for( let tuce = 0; tuce < 5; tuce++ ) {
        //tuce is only visible in here (and in the for() parentheses)
    }

    //tuce is *not* visible out here
}

function byE40() {
    //nish *is* visible out here

    for( var nish = 0; nish < 5; nish++ ) {
        //nish is visible to the whole function
    }

    //nish *is* visible out here
}