@monajs/env-config-webpack-plugin/src/index.js

env-config-webpack-plugin

/**
 * Generate configuration files based on env.
 * @author yangxi | 599321378@qq.com
 **/

const glob = require('glob')
const fs = require('fs-extra')
const path = require('path')
const compose = require('koa-compose')

const resolve = (filePath) => path.resolve(__dirname, filePath)
const logTat = '[@monajs/env-config-webpack-plugin]: '

// dev | sit | pre | production
const defaultEnv = 'production'

class EnvConfigWebpackPlugin {
	constructor (options) {
		this.entry = options.entry
		if (!this.entry) throw new Error(`${logTat}The option \`entry\` is necessary.`)
		this.output = options.output
		if (!this.output) throw new Error(`${logTat}The option \`output\` is necessary.`)
		this.env = options.env || process.env.NODE_ENV || defaultEnv
	}

	// remove output files
	remove (ctx, next) {
		fs.remove(this.output, err => {
			if (err) throw err
			next()
		})
	}

	// get path type, file or dir
	isDir (ctx, next) {
		fs.stat(this.entry, (err, stat) => {
			if (err) throw err
			const res = stat.isDirectory() ? 2 : (stat.isFile() ? 1 : 0)
			if (res === 0) {
				throw new Error(`${logTat}Please check if the path（\`${this.entry}\`） exists`)
			}
			this.isEntryDir = res === 2
			next()
		})
	}

	// ensure output path exists
	// generate json for output path
	action (ctx, next) {
		if (this.isEntryDir) {
			//dir
			fs.ensureDir(this.output, (err) => {
				if (err) throw err
				glob.sync(`${this.entry}/*.json`, {
					matchBase: true
				}).forEach((entry) => {
					const output = entry.replace(this.entry, this.output)
					this.generateJson(entry, output)
				})
			})
		} else {
			//file
			fs.ensureFile(this.output, (err) => {
				if (err) throw err
				this.generateJson(this.entry, this.output)
			})
		}
		console.info(`${logTat}Generate configuration files success!`)
		next()
	}

	// generate json files
	generateJson (entry, ouput) {
		fs.readJson(entry, (err, json) => {
			if (err) throw err
			const data = Object.assign({}, json['common'], json[this.env])
			fs.writeFile(ouput, JSON.stringify(data, null, '\t'), (err) => {
				if (err) throw err
				console.info(`${logTat} ${ouput}`)
			})
		})
	}

	end (ctx, next, callback) {
		callback()
	}

	apply (compiler) {
		// exec once
		compiler.plugin('run', (complication, callback) => {
			compose([
				this.remove.bind(this),
				this.isDir.bind(this),
				this.action.bind(this),
				this.end.bind(this, callback)
			])()

		})
	}
}

module.exports = EnvConfigWebpackPlugin