Refactor to support plugin like babel

[sibelius]

Babel plugin object example:

type PluginObject = {
  pre?: Function;
  post?: Function;
  manipulateOptions?: Function;

  visitor: ?{
    [key: string]: Function | {
      enter?: Function | Array<Function>;
      exit?: Function | Array<Function>;
    }
  };
};

each babel plugin returns an object like this.

we should think in CreateGraphQL PluginObject as well.

---

• Separate mongoose schema to a plugin;
• Separate relay templates to a plugin (figure out how to best do this);
• Create boilerplate projects for Create-GraphQL plugins;
• Handle plugins property on .graphqlrc.

[sibelius]

First draft of Plugins

Read Database Schema Plugins

Motivation

A read schema plugin should read a schema (collection/table definition) and return an object describing it.

Examples

• create-graphql-mongoose
• create-graphql-mysql
• create-graphql-postgres
• create-graphql-rethinkdb

Templates Plugins

Motivation

CreateGraphql should output a different file for a different option provided, for instance: output a raw mutation or a relay mutation

Examples

• create-graphql-type-raw
• create-graphql-type-relay
• create-graphql-mutation-raw
• create-graphql-mutation-relay

we need to define inputs and outputs of these plugins

[lucasbento]

I can imagine it to handle schema from multiple types of databases but how would that be for different templates?

[lucasbento]

Also, how do you plan on starting, should #43 wait for it?

Turning the mongoose schema reading into a plugin should be really straightforward.

We should also have a plugins property on .graphqlrc.

[sibelius]

A template plugin could have an option parameter, like -t for template

[lucasbento]

A template plugin could have an option parameter, like -t for template

@sibelius: what do you mean?

I meant, how will we implement a template plugin? Will we prepare all the variables, pass it to the plugin and it will return the files?

[sibelius]

Yep, I think so, we need to define the inputs and outputs of each plugin

[lucasbento]

So, I started working on this, I thought the following as a blueprint for a create-graphql-plugin:

export default {
  pre: (arguments) => {
    const {
      config, // The content of `.graphqlrc`, will be the default if it doesn't exist
    } = arguments;

    console.log('this is a pre hook function');

    return {
      fields, // The fields generated on the plugin
      files, // Array of objects, e.g.: [{ name: 'ExampleAddMutation.js', content: 'Content of file }]
    };
  },
  post: (arguments) => {
    const {
      config, // The content of `.graphqlrc`, will be the default if it doesn't exist,
      fields, // The fields of the schema
    } = arguments;

    console.log('this is a post hook function');

    return {}; // What would this return?
  },
};

Would love your opinions on this, @sibelius & @felippepuhle.

Also, the plugins would be installed as a devDependency and specified on .graphqlrc under plugins, e.g.:

{
  "directories": {
    ...
    "connection": "connection",
    "loader": "loader",
    "model": "model",
    ...
  },
  "plugins": [
    "create-graphql-plugin-mongoose",
    "create-graphql-plugin-sequelize",
    ...
  ]
}

The generator would then call each plugin based on the order defined, so it would call the mongoose one and then sequelize with the results brought from mongoose.

Still have to figure out how we will deal with files.

[lucasbento]

Good content on Babel plugins: https://github.com/thejameskyle/babel-handbook/blob/master/translations/en/plugin-handbook.md