public/subjects/griswold-the-blacksmith

Griswold the Blacksmith

Methods and built-in functions are good, but most of the time we have to write our own logic and the first block for that are conditions.

The if keyword

The if keyword allows you to run lines of code only if the condition is right, example:

if (age > 48) {
  console.log('You are over 48 years old')
}

Condition ()

following our if is a condition delimited by () parentheses,

Comparaison operators >

Inside our condition is a comparaison (using the greater than operator >).
This code if (age > 48) reads:

If age is greater than 48, then do the following code

There are 6 different comparaison opperators:

• > greater than
• < lesser than
• <= lesser than or equal
• >= greater than or equal
• === equal to
• !== not equal to

Every comparaison operator are like functions, they take 2 arguments, one on the right and one on the left, and returns a boolean value. Either true, if the condition is met, or false if it's not.

Since they return value, you can assign them to variables, just like functions return values:

let age = 5
let ageEqual5 = age === 5 // age is equal to 5
let ageNotEqual5 = age !== 5 // age is not equal to 5
console.log(ageEqual5) // true
console.log(ageNotEqual5) // false

But they are commonly used directly inside an if condition.

Scope {}

After the condition, a curly brace { signal the begining of a scope. The scope ends at the enclosing } a few lines after.

Scopes are a way to group lines of code, this allow us to do multiple lines of code if a condition is true.

if (age > 48) { // <-beginning of the scope of the if condition
  console.log('You are over 48 years old')
} // <- end of the scope of the if condition

Indentation .. (2 spaces)

Upon writing code inside a scope, it's an important convention to indent it.

Indenting is when spaces are added at the beginning of the line, here is an example of bad code:

if (age > 48) {
// <- without indentation ! bad bad ! unreadable !!
console.log('You are over 48 years old')
}

good code:

if (age > 48) {
  // <- with indentation, omg so clean, amazing !
  console.log('You are over 48 years old')
}

Indenting add a visual indication that the code is inside a scope, while it's not strictly necessary for code to work, it will become very important to keep the code clear.

Instructions

You are Griswold the Blacksmith, and you must give the list of items the player can buy with the money he has, here is what you are selling:

• arrows for 3 coins
• boots for 44 coins
• sword for 299.99 coins (limited offer)

Declare a purchasableGoods array and conditionally push to it all the goods that the player can buy.

Use if conditions and compare the cost of the goods with the provided variable playerCoins that contains the number of coins available to the player.

You must order elements by price