npm i -D postcss-load-plugins

npm i -S|-D postcss-plugin

Install plugins and save them to your package.json dependencies/devDependencies.

package.json

Create postcss section in your projects package.json.

App
  |– client
  |– public
  |
  |- package.json

{
  "postcss": {
    "plugins": {
      "postcss-plugin": {}
    }
  }
}

.postcssrc

Create a .postcssrc file.

App
  |– client
  |– public
  |
  |- (.postcssrc|.postcssrc.json|.postcssrc.yaml)
  |- package.json

JSON

{
  "plugins": {
    "postcss-plugin": {}
  }
}

YAML

plugins:
  postcss-plugin: {}

postcss.config.js or .postcssrc.js

You may need some JavaScript logic to generate your config. For this case you can use a file named postcss.config.js or .postcssrc.js.

App
  |– client
  |– public
  |
  |- (postcss.config.js|.postcssrc.js)
  |- package.json

Plugins can be loaded in either using an {Object} or an {Array}.

{Object}

module.exports = (ctx) => ({
  plugins: {
    'postcss-plugin': ctx.plugin
  }
})

{Array}

module.exports = (ctx) => ({
  plugins: [
    require('postcss-plugin')(ctx.plugin)
  ]
})

Plugin options can take the following values.

{}: Plugin loads with defaults

'postcss-plugin': {} || null

:warning: {} must be an empty object

{Object}: Plugin loads with options

'postcss-plugin': { option: '', option: '' }

false: Plugin will not be loaded

'postcss-plugin': false

Order

Plugin order is determined by declaration in the plugins section.

{
  plugins: {
    'postcss-plugin': {}, // plugins[0]
    'postcss-plugin': {}, // plugins[1]
    'postcss-plugin': {}  // plugins[2]
  }
}

Context

When using a function (postcss.config.js), it is possible to pass context to postcss-load-plugins, which will be evaluated before loading your plugins. By default ctx.env (process.env.NODE_ENV) and ctx.cwd (process.cwd()) are available.

postcss.config.js

module.exports = (ctx) => ({
  plugins: {
    postcss-import: {},
    postcss-modules: ctx.modules ? {} : false,
    cssnano: ctx.env === 'production' ? {} : false
  }
})

const { readFileSync } = require('fs')

const postcss = require('postcss')
const pluginsrc = require('postcss-load-plugins')

const css = readFileSync('index.css', 'utf8')

const ctx = { modules: true }

pluginsrc(ctx).then((plugins) => {
  postcss(plugins)
    .process(css)
    .then((result) => console.log(result.css))
})