let of javascript code example

Example 1: var vs let js

let: //only available inside the scope it's declared, like in "for" loop, 
var: //accessed outside the loop "for"

Example 2: let in javascript

The let statement declares a block scope local variable, optionally initializing it to a value.

let x = 1;

if (x === 1) {
  let x = 2;

  console.log(x);
  // expected output: 2
}

console.log(x);
// expected output: 1

Example 3: javascript for of loop

for (variable of iterable) {
  statement
}

Example 4: mdn for..of

function* fibonacci() { // a generator function
  let [prev, curr] = [0, 1];
  while (true) {
    [prev, curr] = [curr, prev + curr];
    yield curr;
  }
}

for (const n of fibonacci()) {
  console.log(n);
  // truncate the sequence at 1000
  if (n >= 1000) {
    break;
  }
}

Example 5: let javascript

var i = "global";
function foo() {
    var i = "local"; // Otra variable local solo para esta función
    console.log(i); // local
}
foo();
console.log(i); // global