04

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eloquent.js book club - session	/04/index.html

eloquent.js book club - session #4

Chapter 3, Functions

We might use a digital "whiteboard".

There's a transcript of the session.

Some questions

Let's refresh a few things this chapter uses:

• What does console.log(false || 3); print?
• What about console.log(null || "yay");?

Growing functions

• Did you think of a different way to generalize the padding? Did you expect something else?

• Implement padWith(padding, value, length).

    console.log(padWith(" ", 42, 3))
    // -> " 42"
    console.log(padWith("_", 1, 5))
    // -> "____1"
    console.log(padWith(" ", "Words!, 10))
    // -> "    Words!"
  

• Mhh... what if you want the padding to be an optional argument? How would that work?

    console.log(pad(42, 3))
    // -> " 42"
    console.log(pad(42, 4, "0"))
    // -> "0042"
  

  You could even make the length argument optional...

Other things

Homework: Greetings

Let's imagine we had a function to greet people:

greet("Jane");
// -> "Hi, Jane!"

And maybe we want it to also count how many people it greeted:

var count = 0;

greetAndCount("Jane");
// -> "Hi, Jane!"

greetAndCount("Alice");
// -> "Hi, Alice!"

console.log(count);
// -> 2

And finally, let's also complain if someone comes in twice in a row:

greetOnce("Jane");
// -> "Hi, Jane!"

greetOnce("Jane");
// -> "Hey, you just came in, how did you do that?"

greetOnce("Alice");
// -> "Hi, Alice!"

greetOnce("Jane");
// -> "Hi, Jane!"

How would you implement that?