@pkmn/data

@pkmn/data

A higher level data API wrapper compatible with @pkmn/sim and @pkmn/dex.

Installation

$ npm install @pkmn/data

Alternatively, as detailed below, if you are using @pkmn/data in the browser and want a convenient way to get started, simply depend on a transpiled and minified version via unpkg:

<script src="https://unpkg.com/@pkmn/dex"></script>
<script src="https://unpkg.com/@pkmn/data"></script>

In this example, @pkmn/dex is included as well, because @pkmn/data requires a Dex implementation to be useful.

Usage

This package can be used to wrap an implementation of the Pokémon Showdown @pkmn/dex-types to provide an alternative data layer API. This package is not generally useful without a runtime dependency - you must bring your own data layer. You almost certainly should be using @pkmn/dex instead of @pkmn/sim unless you know what you are doing.

import * as dex from '@pkmn/dex';
import * as sim from '@pkmn/sim';
import {Dex} from '@pkmn/dex-types';
import {Generations} from '@pkmn/data';

// dex.Dex implements the @pkmn/dex-types's Dex directly, so this just works without complaints
const dexGens = new Generations(dex.Dex);

// All of the types from sim.Dex don't actually line up perfectly, but casting sidesteps that
const simGens = new Generations(sim.Dex as uknown as Dex);

Generations

The Generations object provides an alternative, higher-level data API to Dex which irons out a couple of Pokémon Showdown quirks. While this interface is far from the optimal design, it aims to be slightly more ergonomic and intuitive to use than Dex.

• data returned from a Generations methods are constrained to the generation in question. Data which does not exist, only exists in later gens, or is illegal or non standard will not be returned which means you do not need filter data before using it.
• undefined is returned from functions as opposed to an object with its exists field set to false. undefined fails loudly, can be checked statically by Typescript and allows for more efficient implementation under the hood.
• methods are moved to more intuitive locations than all existing on Dex (eg. Species#hasAbility).
• Types is overhauled to hide Pokémon Showdown's enum-based type effectiveness handling.
• the 'sub-API' fields of Generation all have a get method and can be iterated over (save for Generation#effects).
• a stats API including calculation logic is provided via Generation#stats.

Generations handles existence at the field level slightly differently than at the object level - references in fields which point to objects that do not exist in the generation will be updated to remove those objects, but fields which should not be relevant at all to an earlier generation are not pruned. For example, Chansey's prevo field in Gen 3 will not be happiny, but a move from the same generation may still have its zMove.basePower field populated as it should never be queried in Gen 3 anyway. This is mostly an artifact of how the Pokémon Showdown Dex Generations is built on top of works - for efficiency reasons its only worthwhile to clean up the fields which are actually relevant to the generation in question.

import {Dex} from '@pkmn/dex';
import {Generations} from '@pkmn/data';

const gens = new Generations(Dex);
assert(gens.get(1).types.get('Psychic').damageTaken['Ghost'] === 0);
assert(gens.get(5).species.get('Gengar').hasAbility('Levitate'));
assert(Array.from(gens.get(1).species).length === 151);

Please see the unit tests for more comprehensive usage examples.

Browser

The recommended way of using @pkmn/data in a web browser is to configure your bundler (Webpack, Rollup, Parcel, etc) to minimize it and package it with the rest of your application. If you do not use a bundler, a convenience production.min.js is included in the package. You simply need to depend on ./node_modules/@pkmn/data/build/production.min.js in a script tag (which is what the unpkg shortcut above is doing), after which Generations will be accessible as a global.

Limitations

This package is heavily constrained by Pokémon Showdown's data layer - because it simply serves as a wrapper to the Dex it cannot doing anything too ambitious or making suitable optimizations. As such, this package does not attempt to provide the 'ideal' data layer for any and all Pokémon projects - please see the Pokémon Showdown Core design doc which provides details on a design for the ambitious goal of providing a powerful, type-safe and well thought out API that allows clients to only depend on the data they need.

License

This package is distributed under the terms of the MIT License. Substantial amounts of the code have been derived from the portions of the Pokémon Showdown client which are distributed under the MIT License.