livetodolist.js

#!/usr/bin/env node

const fs = require('fs')
const Path = require('path')
const stateFilePath = Path.resolve(process.env.HOME, '.todo')

const command = process.argv[2]
const input = process.argv.slice(3).join(' ')

const getState = callback => {
  fs.readFile(stateFilePath, (error, json) => {
    if (error){
      if (error.message.includes('no such file or directory')){
        return callback({})
      }else{
        throw error
      }
    }
    let state
    try{
      state = JSON.parse(json)
    }catch(error){
      state = {}
    }
    callback(state)
  })
}

const setState = (state, callback) => {
  fs.writeFile(stateFilePath, JSON.stringify(state), 'utf8', (error) => {
    if (error) throw error
    callback()
  })
}

const usage = () =>
  console.warn(
`
Usage:
  todo add "buy some milk"
  todo list
  todo complete $TODO_ID
  todo delete $TODO_ID
`
  )

const commands = {
  add: (state, input, callback) => {
    state.lastId = state.lastId || 0
    state[++state.lastId] = {value: input}
    setState(state, () => {
      console.log('added item:')
      console.log(`  ${state.lastId}: ${input}`)
      callback()
    })
  },

  list: (state, input, callback) => {
    Object.keys(state).forEach(todoId => {
      if (todoId.match(/^\d+$/)){
        console.log(`${todoId}: ${state[todoId].complete ? '[X]' : '[ ]'} ${state[todoId].value}`)
      }
    })
    callback()
  },

  complete: (state, todoId, callback) => {
    const todo = state[todoId]
    if (todo){
      todo.complete = true;
      setState(state, () => {
        console.log(`completed: ${todo.value}`)
      })
    }else{
      console.warn(`unable to find todo ${todoId}`)
      process.exit(1)
    }
  },

  uncomplete: (state, todoId, callback) => {
    const todo = state[todoId]
    if (todo){
      todo.complete = false;
      setState(state, () => {
        console.log(`uncompleted: ${todo.value}`)
      })
    }else{
      console.warn(`unable to find todo ${todoId}`)
      process.exit(1)
    }
  },

  delete: (state, todoId, callback) => {
    if (todoId in state){
      const value = state[todoId].value
      delete state[todoId]
      setState(state, () => {
        console.log(`deleted: ${value}`)
      })
    }else{
      console.warn(`unable to find todo ${todoId}`)
      process.exit(1)
    }
  }
}


getState(function(state){
  if (command in commands){
    commands[command](state, input, (error) => {
      if (error){
        console.error(error)
        process.exit(1)
      }else{
        process.exit(0)
      }
    })
  }else{
    usage()
    process.exit(1)
  }
})