1.1 - Output & the Console

Review:
We will be programming in an IDE - several IDE's exist.

We will be backing-up our code to Github, an internet-based version control system.

JavaScript's entrypoint is the top of the script file - you don't need a main() function.

To print something to the console in JS, the command is console.log(x) where x is whatever you want to print.

1.1 - Output & the Console

Output to the user is crucial in programming:

• Most programming languages have a console of sorts to print text and numbers.

  • Very similar formatting can be used in most languages to add new lines (\n) or tabs (\t), etc.

    • Those are called "escape sequences". To print a slash, you need \\\

• JavaScript uses an object called console to print or interact with the console window.

• Depending on the version of JavaScript, your console may or may not have the following:

  • console.log() - similar to a "captain's log" or journal entry, print to the console

  • console.info() - more for the developer, print potentially important info to the console

  • console.error() - a specific call to print an error message to the console

  • console.time(name) - start a timer with the give name (text)

  • console.timeLog(name) - print the current elapsed time for timer name

  • console.timeEnd(name) - stop the timer named name

In-Class Practice (lead by the teacher):

• Every web browser is built on top of HTML and JavaScript. This means your browser has a console.

  • Open a chrome browser window and visit www.brash.ca.
    Then hit CTRL+SHIFT+J  (on a Mac it's OPTION+COMMAND+J)
    This will be different for other browsers - if you aren't using Chrome, you're on your own.

    • This should bring up the developer tools and it should have highlighted the "console" tab. The "console" is like the brain of JavaScript, taking commands and giving output. 

  • Click into the console where you see a ">" chevron, this is the terminal (console) waiting for a command.

  • Type console.log("Hello World!") and hit enter.

  • Now type into the console document.write("Hello World!") hit enter and see where the output goes.

  • Try console.time("test") hit enter, wait a bit and then console.timeEnd("test")

    • ❓ What might this be useful for?

  • Thankfully we won't have to work in the browser's console window for this course!