jotson/loottable.js

A loot drop table implementation in JavaScript

LootTable.js

A loot drop table implementation in JavaScript.

LootTable is used to make a random choice among a weighted list of alternatives for item drops, map generation, and many other processes. There's a good overview of loot tables on Lost Garden.

Example

var loot = new LootTable();
loot.add('sword', 20);
loot.add('shield', 5);
loot.add('gold', 5);
loot.add(null, 1);
var item = loot.choose(); // most likely a sword, sometimes null

Weights are arbitrary, not percentages, and don't need to add up to 100. If one item has a weight of 2 and another has a weight of 1, the first item is twice as likely to be chosen. If quantity is given, then calls to choose() will only return that item while some are available. Each choose() that selects that item will reduce its quantity by 1.

Items can be anything, not just strings. They can be arrays, numbers, JSON data, null, functions... even another LootTable!

Building

npm install
npm run build

Global script example

include a <script src="LootTable.js"></script> tag on your page and you can use loot table as a global variable.

ES modules example

import LootTable from 'loot-table';

CommonJS (node) example

var LootTable = require('loot-table');

loottable.js's Issues

Suggestion: Improve Performance by precomputing full table

to improve the performance of choose, you should rebuild an array of the weighted choices.

This will front load all performance cost to the construction of the loot pool (ideally, once) instead of it being rebuilt every loot choice.

Then choose can be a simple return this.cachedArray[randomIndex];

Update to support latest ECMAScript

I've been looking for a good loot table to implement into a Discord bot, and so far this seems like the best option. But I can see this was last updated 3 years ago and doesn't support the latest changes in ECMAScript. E.g. Replace "var" with let and const.

Is there any plans for a future update? Would love to be able to use this without any possible issues.

adding es modules support

@jotson would you be open to this? Happy to send a pull request if so.