Read write JSON - Tabris.js

test-json.js

const {Button, fs, TextInput, ui} = require('tabris')

const FILE = fs.filesDir + '/' + 'names.json'

const RIGHT_MARGIN = 10
const LEFT_MARGIN = 10

let names = [
  {
    'firstName': 'Bob',
    'lastName': 'Jones'
  },
  {
    'firstName': 'Jill',
    'lastName': 'Willard'
  }

]

console.log(JSON.stringify(names))

names.forEach((name, index) => {
  let txiFirstName = new TextInput({
    id: 'txiFirstName' + (index),
    top: 'prev() 10',
    text: name.firstName
  }).appendTo(ui.contentView)

  txiFirstName.on('textChanged', () => {
    txiFirstName.borderColor = '#0f0'
    name.firstName = txiFirstName.text
    console.log('textChanged: \nname.firstName = ' + name.firstName)
    console.log(JSON.stringify(names))
  })

  let txiLastName = new TextInput({
    id: 'txiLastName' + (index),
    top: 'prev() 10',
    text: name.lastName
  }).appendTo(ui.contentView)

  txiLastName.on('textChanged', () => {
    name.lastName = txiLastName.text
  })
}) // end forEach

let btnReadFile = new Button({
  centerX: 0, top: 'prev() 10', width: 200,
  text: 'Read File: ' + FILE
}).appendTo(ui.contentView)

btnReadFile.on('select', () => {
  readFile(FILE. names)
  console.log(JSON.stringify(names))
})

let btnWriteFile = new Button({
  centerX: 0, top: 'prev() 10', width: 200,
  text: 'Write File: ' + FILE
}).appendTo(ui.contentView)

let btnRemoveFile = new Button({
  centerX: 0, top: 'prev() 10', width: 200,
  text: 'Remove File: ' + FILE
}).appendTo(ui.contentView)

btnWriteFile.on('select', () => {
  let jnames = JSON.stringify(names)
  fs.writeFile(FILE, jnames, 'utf-8')
    .then(() => {
      console.log('file written:', FILE)
      txiFile.text = jnames
      console.log(JSON.stringify(names))
    }
    )
    .catch(err => console.error(err))
})

btnRemoveFile.on('select', () => {
  fs.removeFile(FILE)
    .then(() => console.log('file removed:', FILE))
    .catch(err => console.error(err))
})

let txiFile = new TextInput({
  top: 'prev() 20', left: 5, right: 5,
  type: 'multiline'
}).appendTo(ui.contentView)

function readFile (filename, names) {
  fs.readFile(FILE, 'utf-8')
    .then(text => txiFile.text = text)
    .then(text => {
      names = JSON.parse(text)
      console.log(JSON.stringify(names))
      readNames(names)
    })
    .catch(err => console.error(err))
}

function readNames (names) {
  names.forEach((name, index) => {
    let t = '#txiFirstName' + index
    ui.contentView.apply({[t]: {text: name.firstName}})
    console.log(JSON.stringify(names))
  })
}