CODEWITHSUNDEEP
javascript
killahtree
killahtree

Reputation: 41

What is this called (JS)

var logic = {
    Rock: { w:"Scissors", l:"Paper"},
    Paper: {w:"Rock", l:"Scissors"},
    Scissors: {w:"Paper", l:"Rock"},
};

and it is used like:

logic[playChoice].w === rndChoice

Found it in a JS rock paper scissors example, curious what logic is called.

Please let me know if this is the wrong place...

Upvotes: 3

Views: 111

Answers (3)

GammaGames
GammaGames

Reputation: 1820

Given:

var logic = {
    Rock: { w:"Scissors", l:"Paper"},
    Paper: {w:"Rock", l:"Scissors"},
    Scissors: {w:"Paper", l:"Rock"},
};

logic[playChoice].w === rndChoice

logic is an object. Just a regular object with the properties Rock, Paper, and Scissors. Each of these properties are also objects, each with a win property (w) and a loss property (l). These properties are set to the string values of each available input.

The comparison (===) uses two variables not previously defined, playChoice, provided by the player and rndChoice, provided by the computer. If the w property for the object in the property for playChoice equals the rndChoice the comparison is true, and the player wins the round.

For example:

  1. We play Rock
  2. The computer plays Scissors
  3. The left side of the comparison gets the w property of logic["Rock"], or "Scissors"
  4. the left side matches the right side that was selected by the computer
  5. The comparison is true, the player has won the round

Upvotes: 4

alex067
alex067

Reputation: 3281

The logic here is accessing an attribute of object "logic" with a given key.

The object "logic" here is a nested object, where the keys are in itself objects as well.

If playChoice === Rock then we are accessing the Rock object from the logic object, and grabbing the "w" attribute from Rock.

Upvotes: 0

Isti115
Isti115

Reputation: 2748

If you are asking about the exact javascript structure that is being used here in the variable called logic, to store the data, that is just a nested* object, created via an object literal.
(https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Object_initializer)

*: Meaning, that the values stored in the object are objects themselves as well.

In case you are curious about the more generic answer, things assigning values to keys are usually referred to as maps. (When the values are consecutive numbers starting from zero, we essentially get an array.)

I strongly recommend that you read through this to get a better understanding:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Working_with_Objects

Upvotes: 2

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