emath.js

eMath.js is a JavaScript library designed to provide tools for incremental game development, built upon break_eternity.js. It provides classes for upgrades, saving/loading, and more!

Abstract

This project started when I was trying to create my first incremental game. I found it difficult to implement certain systems like upgrades and saving. When I eventually made those systems, I wanted to make a package so I could streamline those tools. After a few months of development, I have finally developed it into a presentable state (I should have started it with v0.1.0 instead of v1.0.0 . . .).

Note: This package uses break_eternity.js by exporting the class Decimal directly. You should import the Decimal class from emath.js instead of break_eternity.js. For example,

import { Decimal } from "emath.js";

const num1 = new Decimal(10);
const num2 = num1.add(5);

const num3 = new Decimal(20);
const num4 = Decimal.pow(num1, num3);
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This was done in order to implement the saving/loading system using class-transformer and reflect-metadata (which are the only dependencies of this package).

You cannot import directly from break_eternity.js as the package targets a version of javascript (es5) that is not supported by class-transformer and reflect-metadata.

Example Usage

This is a simple example of how to use the package. It creates a game with a currency called "coins" and an upgrade for that currency. It also includes hotkeys for gaining coins and buying upgrades, as well as saving and loading the game.

Note: This example uses javascript. It is recommended to use typescript for better type checking.

import { Decimal } from "emath.js";
import { Game } from "emath.js/game";

// For CDN usage:
// const { Decimal, Game } = eMath; 

// Initialize game
const coinGame = new Game();

// Create a new currency with upgrades
const coins = coinGame.addCurrency("coins", [
    {
        id: "upg1Coins", // Unique ID
        cost: level => level.mul(10), // Cost of 10 times the level
        maxLevel: new Decimal(1000),
        effect: (level, upgradeContext, currencyContext) => {
            // `level` is the level of the upgrade
            // `upgradeContext` is the context of the upgrade (this upgrade)
            // `currencyContext` is the context of the currency (coins in this case)

            // Access the `boost` object to add a boost
            currencyContext.boost.setBoost({
                id: "boostUpg1Coins", // Unique ID of the boost
                // Effect of the boost, which is additive, 11 times the level of the upgrade
                value: n => n.plus(level.mul(11)).sub(1),
            });
        },
    },
    // Add more upgrades here ...
]);

// Initialize / Load game
coinGame.init();
coinGame.dataManager.loadData();

// Gain coins
coins.gain();

// Buy (max) upgrades
coins.buyUpgrade("upg1Coins");

// Hotkeys
coinGame.keyManager.addKey([
    {
        id: "gainCoins",
        name: "Gain Coins",
        key: "g",
        onDownContinuous: () => coins.gain(),
    },
    {
        id: "buyUpgrades",
        name: "Buy Upgrades",
        key: "b",
        onDownContinuous: () => coins.buyUpgrade("upg1Coins"),
    },
]);

// Saving and Loading
window.addEventListener("beforeunload", () => {
    coinGame.dataManager.saveData();
});
coinGame.eventManager.setEvent("autoSave", "interval", 30000, () => {
    coinGame.dataManager.saveData();
    console.log("Auto Saved!");
});
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Installation

Install via npm (recommended)

npm install emath.js
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Include using CDN

Include the following script in your HTML file. It will set the global variable eMath to the window object.

Note: There is no development build for CDN, as it is used for nodejs. Replace @latest with the version you want to use. (e.g. @8.3.0), or use @latest for the latest version.

emath.js

<script src="https://cdn.jsdelivr.net/npm/emath.js@latest/dist/main/eMath.min.js"></script>
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emath.js/game

Also includes "emath.js" so you only need to include this script.

<script src="https://cdn.jsdelivr.net/npm/emath.js@latest/dist/game/eMath.game.min.js"></script>
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emath.js/presets

Sets the global variable eMathPresets to the window object.

Note: This does not include either "emath.js" or "emath.js/game".

<script src="https://cdn.jsdelivr.net/npm/emath.js@latest/dist/presets/eMath.presets.min.js"></script>
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Check out the documentation!