JavaScript console

looking at JavaScript variables without displaying them

For debugging purposes, we can output any processed data without directly affecting the program using console logging or console.log:

const aVariable = "Application ready"
// a piece of text 

console.log(aVariable) 
// outputs "Application ready" 

We can access the console by

• loading the page that contains the script on the browser

• right-clicking on the page

• clicking on "Inspect" (or similar)

• finding the "Console" tab:

Thus, we can see what happens to our code without directly displaying it on the browser!

Another example

In app.js once again, we could use console.log as a calculator:

const aVariable = 2 + 3
// an assignment to a variable

console.log(aVariable) 
// outputs 5

...checking a variable made of other variables:

const firstNumber = 2     
// this could come from user input
const secondNumber = 3    
// this could come from an external file

const aVariable = firstNumber + secondNumber
// adding the above two together

console.log(aVariable) 
// outputs 5

Wwe can see how console.log enables us to see outputs of sensitive calculations without showing them directly on the webpage!