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JavaScript In Practice: ES6 And Beyond

Exercise on Function Scope, Block Scope, Constants

Explore ES6 improvements on function and block scope along with constants by working through code exercises. Learn to predict console outputs, modify code without changing logging statements, and deepen your understanding of JavaScript scope rules and constants management.

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Exercise 1

Check the following code snippet riddle:

Determine the values logged to the console before you execute it.

Node.js
'use strict';
var guessMe1 = 1;
let guessMe2 = 2;
{
 
    try {
        console.log( guessMe1, guessMe2 ); // (A)
    } catch(err) {
        console.log("Error");
    }
    
    let guessMe2 = 3;
    console.log( guessMe1, guessMe2 ); // (B)
}
console.log( guessMe1, guessMe2 ); // (C)
const print_func = () => {
    console.log( guessMe1 ); // (D)
    var guessMe1 = 5;
    let guessMe2 = 6;
    console.log( guessMe1, guessMe2 ); // (E)
};
console.log( guessMe1, guessMe2 ); // (F)

Explanation

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