<-- Back to Snippets

How to Prototype a Class

Prototyping allows you to extend default class functionality for Player's, Vehicle's, etc.

It is important to understand that all Prototype files should be loaded immediately after your database initialization. Granted your Prototype has database features.

While you are creating prototypes keep in mind that the data stored in a prototype is not accessible in another resource. Prototypes can only be defined in the resource that it is running inside of.

This means that if you have a function called player.subCash in a resource called example. In another resource called example2 that function is inaccessible.

Limitations and Performance with Prototyping

While prototypes seem like a handy way to get accessible functions, data, etc. keep in mind that the data that is stored on a player has to be transferred between resources, and sometimes even events. Try to keep the data you store on a Player, or a Vehicle relatively small.

Javascript Example

alt.Player.prototype.emitMeta = function emitMeta(key, value) {
    if (typeof value === 'function') {
        throw new Error(`Value cannot be a function. emitMeta.prototype`);
    }

    this.setMeta(key, value);
    alt.emitClient(this, 'meta:Emit', key, value);
};

alt.Player.prototype.init = function init() {
    this.data = {};
};

alt.Player.prototype.syncCash = function syncCash() {
    this.emitMeta('cash', this.data.cash);
};

alt.Player.prototype.setCash = function setCash(value) {
    if (isNaN(value)) {
        throw new Error(`Value is not a number. setCash.prototype`);
    }

    if (!this.data) {
        this.data = {};
    }

    this.data.cash = value;
    this.syncCash();
};

alt.Player.prototype.subCash = function subCash(value) {
    if (isNaN(value)) {
        throw new Error(`Value is not a number. subCash.prototype`);
    }

    if (!this.data) {
        this.data = {};
    }

    const absValue = Math.abs(parseFloat(value)) * 1;
    if (this.data.cash < absValue) {
        return false;
    }

    this.data.cash -= absValue;
    this.data.cash = Number.parseFloat(this.data.cash).toFixed(2) * 1;
    this.syncCash();
    return true;
};

alt.Player.prototype.addCash = function addCash(value) {
    if (isNaN(value)) {
        throw new Error(`Value is not a number. addCash.prototype`);
    }

    if (!this.data) {
        this.data = {};
    }

    const absValue = Math.abs(parseFloat(value));
    if (this.data.cash + absValue > 92233720368547757) {
        absValue = 92233720368547757;
    }

    this.data.cash += absValue;
    this.data.cash = Number.parseFloat(this.data.cash).toFixed(2) * 1;
    this.syncCash();
    return true;
};

Typescript Server Side Example

// Use `alt-client` to do prototyping on client-side.
declare module 'alt-server' {
    export interface Player {
        cash?: number;
        bank?: number;

        // You must declare your function interfaces.
        addToCash(value: number): boolean;
        addToBank(value: number): boolean;
    }
}

// Then you can define your prototype functions.
alt.Player.prototype.addToCash = function addToCash(value: number) {
    if (!this.cash) {
        this.cash = value;
    } else {
        this.cash += value;
    }

    return true;
};

alt.Player.prototype.addToBank = function addToBank(value: number) {
    if (!this.bank) {
        this.bank = value;
    } else {
        this.bank += value;
    }

    return true;
};

Real World Example

player.init();
player.emitMeta('test', true);
player.setCash(25);
player.subCash(5);
player.addCash(2);