Vue DIOD

Dependency Injection in Vue.js thanks to DIOD library.

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Documentation & Examples | DIOD on GitHub

About

As stated by its author on GitHub, DIOD is:

A very opinionated and lightweight (under 2kB minified and gzipped) inversion of control container and dependency injector for Node.js or browser apps. It is available for vanilla Javascript usage but its true power will be shown by building Typescript apps.

Vue DIOD is made on top of DIOD and helps avoiding SOLID principles violations in Vue 3 applications. It allows to configure dependencies at the app level and / or at component level, without children knowing abour the actual implementations.

Basically, it wraps DIOD functionalities in a plugin which uses Vue's provide method to make dependencies available to subtree components, by calling inject with the registered abstract class as key.

It also provides its builder for bootstrapping dependencies at component level, and a composable which main purpose is helping with injection key typings.

Quick example (with plugin)

Define abstraction

export abstract class AbstractCounter {
  increment(value: number): number;
  decrement(value: number): number;
}

Create implementation

export class Counter implements AbstractCounter {
  public increment(value: number): number {
    return value + 1;
  }

  public decrement(value: number): number {
    return value - 1;
  }
}

Bootstrap dependency container

In your main.ts file, for example.

import('reflect-metadata');

// ...

app.use(VueDiod, {
  injectables: [{ register: AbstractCounter, use: Counter }],
});

// ...

Inject in component

Without helper

NB: Keeping your application decoupled from Vue DIOD.

In the component's <script setup>.

// ...

import type { InjectionKey } from 'vue';
import { inject } from 'vue';

const Key = AbstractCounter as unknown;
const counter = inject<() => AbstractCounter>(
  Key as InjectionKey<AbstractCounter>
  /* Optional fallback */
);

const increment = counter.increment.bind(counter);
const decrement = counter.decrement.bind(counter);

// ...

<template>
  <!-- Use in your template -->
</template>

With Vue DIOD helper

// ...

import { useVueDiod } from 'vue-diod';
const { injectServiceInstance } = useVueDiod();

const counter = injectServiceInstance<AbstractCounter>(
  AbstractCounter
  /* Optional fallback */
);

const increment = counter.increment.bind(counter);
const decrement = counter.decrement.bind(counter);

// ...

For other examples, please check the documentation that provides an example for bootstrapping the container at component level, and demonstrate DIOD's powerful autowire for constructor's dependencies.

Install

Install dependencies

Considering you already have a working Vue 3 project, you'll have to install Vue DIOD with its dependencies: reflect-metadata and obviously diod.

npm

npm install -s vue-diod diod reflect-metadata

yarn

yarn add vue-diod diod reflect-metadata

Typescript configuration

Modify your tsconfig.jsonto include the following settings:

{
  "compilerOptions": {
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  }
}

Vite configuration

As stated in the Vite GitHub issues (here):

The emitDecoratorMetadata flag is intentionally not supported.

To enable this support, we have to disable esbuild and use SWC instead, thanks to the rollup-plugin-swc3 package.

npm install --save-dev @swc/core rollup-plugin-swc3

# OR

yarn add -D @swc/core rollup-plugin-swc3

Then, in our vite.config.js or vite.config.ts file, we simply have to add:

import { defineConfig } from 'vite';
import swc from 'rollup-plugin-swc3';
import vue from '@vitejs/plugin-vue';

export default defineConfig({
  // ...

  plugins: [
    swc({
      jsc: {
        parser: {
          syntax: 'typescript',
          dynamicImport: true,
          decorators: true,
        },
        target: 'es2021',
        transform: {
          decoratorMetadata: true,
        },
      },
    }),
    vue(),
  ],
  esbuild: false,
});

TODO

• [ ] Tests
• [ ] Improve documentation
• [ ] Complete examples in the monorepo packages