simpleCli.js

#! /usr/bin/env node

// NPM ecosystem includes
const parseArgs = require("minimist")
const path = require("path")
const fs = require("fs")

const isUserPipingInput = () => {
  if (process.platform === "win32") return false

  // Check if stdin is explicitly set to a TTY
  if (process.stdin.isTTY === true) return false

  return fs.fstatSync(0).isFIFO()
}

class SimpleCLI {
  CommandFnDecoratorSuffix = "Command"
  async executeUsersInstructionsFromShell(args = parseArgs(process.argv.slice(2))._, userIsPipingInput = isUserPipingInput()) {
    const command = args[0]
    const commandName = `${command}${this.CommandFnDecoratorSuffix}`
    if (this[commandName]) return userIsPipingInput ? this._runCommandOnPipedStdIn(commandName) : this[commandName](process.cwd(), args.slice(1))
    else if (command) this.log(`No command '${command}'. Running help command.`)
    else this.log(`No command provided. Running help command.`)
    return this.helpCommand()
  }

  _runCommandOnPipedStdIn(commandName) {
    this.log(`Running ${commandName} on piped input`)
    let pipedData = ""
    process.stdin.on("readable", function () {
      pipedData += this.read() // todo: what's the lambda way to do this?
    })
    process.stdin.on("end", async () => {
      const folders = pipedData
        .trim()
        .split("\n")
        .map(line => line.trim())
        .filter(line => fs.existsSync(line))

      for (const line of folders) {
        await this[commandName](line)
      }

      if (folders.length === 0)
        // Hacky to make sure this at least does something in all environments.
        // process.stdin.isTTY is not quite accurate for pipe detection
        this[commandName](process.cwd())
    })
  }

  silence() {
    this.verbose = false
    return this
  }

  verbose = true

  log(message) {
    if (this.verbose) console.log(message)
    return message
  }

  get _allCommands() {
    return Object.getOwnPropertyNames(Object.getPrototypeOf(this))
      .filter(atom => atom.endsWith(this.CommandFnDecoratorSuffix))
      .sort()
  }

  // Normalize 3 possible inputs: 1) cwd of the process 2) provided absolute path 3) cwd of process + provided relative path
  resolvePath(folder = "") {
    return path.isAbsolute(folder) ? path.normalize(folder) : path.resolve(path.join(process.cwd(), folder))
  }

  helpCommand() {
    this.log(this.welcomeMessage)
    return this.log(`\nAvailable commands:\n\n${this._allCommands.map(comm => `🖌️ ` + comm.replace(this.CommandFnDecoratorSuffix, "")).join("\n")}\n`)
  }
}

module.exports = { SimpleCLI }