JavaScript 30- Day 9 Study Notes

Day 9 of JavaScript 30 by Wes Bos covered several developer tools available in the console. It offered a quick run-down of tips and tricks. Of course, I have used console.log before and I was somewhat familiar with using the inspection tools. But I hadn’t used much else, and to be honest, I didn’t know about the F12 shortcut before this lesson.

Bos used a simple array of objects named “dogs”.

We worked exclusively in the developer tools console as opposed to seeing changes in the viewport.


Using “%s” allows a variable to be inserted within a string.

The console will show “hello I am a * string!” We can use a template literal to insert a variable.


This will display a warning message on the console.


This will display an error message.


This will display an information message.


If the initial input is true, nothing will display. If false, “That is wrong” will display in the console.

Clearing the console

This was neat. I had previously used the drop-down menu to do this.

Viewing DOM elements


This will display each object in the array with a drop-down menu of its elements.


Counts the number of appearances of ‘Wes”.


This will display the amount of time to fetch data.


This will display the array as a table.

So Day 9 was not really a coding project but a short and concise crash course in using the console.

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