Create a Variable: var

 VARIABLES

There were a lot of changes introduced in the ES6 version of JavaScript in 2015. One of the biggest changes was two new keywords, let and const, to create, or declare, variables. Prior to the ES6, programmers could only use the var keyword to declare variables.

var myName = 'Arya';
console.log(myName);
// Output: Arya

Let’s consider the example above:

  1. var, short for variable, is a JavaScript keyword that creates, or declares, a new variable.
  2. myName is the variable’s name. Capitalizing in this way is a standard convention in JavaScript called camel casing. In camel casing you group words into one, the first word is lowercase, then every word that follows will have its first letter uppercased. (e.g. camelCaseEverything).
  3. = is the assignment operator. It assigns the value ('Arya') to the variable (myName).
  4. 'Arya' is the value assigned (=) to the variable myName. You can also say that the myName variable is initialized with a value of 'Arya'.
  5. After the variable is declared, the string value 'Arya' is printed to the console by referencing the variable name: console.log(myName).

There are a few general rules for naming variables:

  • Variable names cannot start with numbers.
  • Variable names are case sensitive, so myName and myname would be different variables. It is bad practice to create two variables that have the same name using different cases.
  • Variable names cannot be the same as keywords. For a comprehensive list of keywords check out MDN’s keyword documentation.

In the next exercises, we will learn why ES6’s let and const are the preferred variable keywords by many programmers. Because there is still a ton of code written prior to ES6, it’s helpful to be familiar with the pre-ES6 var keyword.

If you want to learn more about var and the quirks associated with it, check out the MDN var documentation.



Instructions:

1.Declare a variable named favoriteFood using the var keyword and assign to it the string 'pizza'.


2.Declare a variable named numOfSlices using the var keyword and assign to it the number 8.


3.Under the numOfSlices variable, use console.log() to print the value saved to favoriteFood.

On the following line, use console.log() to print the value saved to numOfSlices.


Solution:

var favoriteFood = "pizza";
var numOfSlices = 8;
console.log(favoriteFood); // pizza
console.log(numOfSlices); // 8

Comments

Post a Comment

Popular posts from this blog

String Interpolation(*** Template Literals***)

  VARIABLES String Interpolation In the ES6 version of JavaScript, we can insert, or  interpolate , variables into strings using  template literals . Check out the following example where a template literal is used to log strings together: const myPet =  'armadillo' ; console . log ( `I own a pet ${ myPet } .` ); // Output: I own a pet armadillo. Notice that: a template literal is wrapped by backticks  `  (this key is usually located on the top of your keyboard, left of the  1  key). Inside the template literal, you’ll see a placeholder,  ${myPet} . The value of  myPet  is inserted into the template literal. When we interpolate  `I own a pet ${myPet}.` , the output we print is the string:  'I own a pet armadillo.' One of the biggest benefits to using template literals is the readability of the code. Using template literals, you can more easily tell what the new string will be. You also don’t have to worry a...
Read more