Notice: This page requires JavaScript to function properly.
Please enable JavaScript in your browser settings or update your browser.
Let 1/2 | Data Types and Variables
Introduction to JavaScript (staging)
course content

Conteúdo do Curso

Introduction to JavaScript (staging)

Introduction to JavaScript (staging)

1. Introduction
2. JavaScript syntax
3. Data Types and Variables

book
Let 1/2

In the very first chapter of the section we learn that there are three ways to declare a variable:

  • let
  • const
  • var

In the later versions of Javascript language known as ES6(ES2015), the let keyword was introduced. It works better than the var keyword. The variables written with the let keyword can also be overwritten.

let has Block Scope:

Variables declared with the let keyword has block scope and cannot be accessed outside that scope, for example.

1234
if (2 == 2){ let name = 'David' } console.log(name)
copy

As you can see we get an error that says that the name is not defined.
Note:
Don’t worry about the if and == for now they will be covered in the later chapters.

Tarefa
test

Swipe to show code editor

In the following code, a variable named city with the assigned value of Berlin has been given to you. You are also given an if statement that checks whether 4 is greater than 2 or not (for now, don’t worry about the if). Your task is to declare a variable with the same name as above inside the if with the value of London. Display the variable outside the if.

Switch to desktopMude para o desktop para praticar no mundo realContinue de onde você está usando uma das opções abaixo
Tudo estava claro?

Como podemos melhorá-lo?

Obrigado pelo seu feedback!

Seção 3. Capítulo 7
toggle bottom row

book
Let 1/2

In the very first chapter of the section we learn that there are three ways to declare a variable:

  • let
  • const
  • var

In the later versions of Javascript language known as ES6(ES2015), the let keyword was introduced. It works better than the var keyword. The variables written with the let keyword can also be overwritten.

let has Block Scope:

Variables declared with the let keyword has block scope and cannot be accessed outside that scope, for example.

1234
if (2 == 2){ let name = 'David' } console.log(name)
copy

As you can see we get an error that says that the name is not defined.
Note:
Don’t worry about the if and == for now they will be covered in the later chapters.

Tarefa
test

Swipe to show code editor

In the following code, a variable named city with the assigned value of Berlin has been given to you. You are also given an if statement that checks whether 4 is greater than 2 or not (for now, don’t worry about the if). Your task is to declare a variable with the same name as above inside the if with the value of London. Display the variable outside the if.

Switch to desktopMude para o desktop para praticar no mundo realContinue de onde você está usando uma das opções abaixo
Tudo estava claro?

Como podemos melhorá-lo?

Obrigado pelo seu feedback!

Seção 3. Capítulo 7
Switch to desktopMude para o desktop para praticar no mundo realContinue de onde você está usando uma das opções abaixo
We're sorry to hear that something went wrong. What happened?
some-alt