json-di

JSON Dependency Injection

What is it?

json-di is a module for loading and initializing other modules through JSON configuration files. The main reason for this is that JSON files are much easier to modify and analyze than source code directly. They allow tools like generators to understand and modify your application structure and dependencies which otherwise would only be possible with messy templates and brittle abstract syntax tree transformations.

feathers-bootstrap uses it to easily create and configure Feathers applications.

Usage

npm install json-di

json-di requires a data object, a parent filename (usually __dirname) and an optional converter which can run to convert properties and returns a standard Promise:

const di = require('json-di');

di({
  path: { require: "path" },
  otherOption: 'test'
}, __dirname).then(result => {
  // result.path === Node's `path` module
  // otherOption === 'test'
});

require

• { "require": "modulename" } will load the module modulename
• { "require": "./mymodule" } will load mymodule.js relative to the JSON file

options

If the module declared in require returns a function the options property will be passed as the arguments to that function. The function can return a promise in which case it will wait until the promise is resolved. With a mainmodule.js like this:

module.exports = function(options) {
  return new Promise(resolve => {
    setTimeout(() => resolve(`Hello ${options.text}`), 500);
  });
}

A world.js like this:

module.exports = 'World';

And a main.json like this:

{
  "require": "./mainmodule",
  "options": [{
    "text": { "require": "./world" }
  }]
}

json-di can be used like this:

const di = require('json-di');

di({
  require: "./main.json"
}, __dirname).then(result => {
  // result === 'Hello World'
});

License

Copyright (c) 2016

Licensed under the MIT license.