planner.js

const clearScreen = () => {
  const readline = require('readline')
  const blank = '\n'.repeat(process.stdout.rows)
  console.log(blank)
  readline.cursorTo(process.stdout, 0, 0)
  readline.clearScreenDown(process.stdout)
}

const renderContent = (lines, highlightIndex, moveMode) => {
  clearScreen()
  lines.forEach((line, index) => {
    if (index === highlightIndex && moveMode) {
      console.log('' + line);
    } else if (index === highlightIndex) {
      console.log('> ' + line);
    } else {
      console.log('  ' + line);
    }
  })
}

const captureKeyPress = () => {
  let content = 'something\nanything\nnothing'
  let lines = content.split('\n')
  const readline = require('readline');
  let highlightIndex = 0;
  let moveMode = false
  let inputMode = false
  renderContent(lines, highlightIndex, moveMode);
  readline.emitKeypressEvents(process.stdin);
  process.stdin.setRawMode(true);
  process.stdin.on('keypress', (str, key) => {
    if (key.ctrl && key.name === 'c') {
      process.exit();
    } else if (inputMode) {
      console.log(str, key)
    } else if (str === 'j' && highlightIndex < lines.length - 1) {
      if (moveMode) {
        [ lines[highlightIndex], lines[highlightIndex + 1] ] = [ lines[highlightIndex + 1], lines[highlightIndex] ]
      }
      highlightIndex++
    } else if (str === 'k' && highlightIndex > 0) {
      if (moveMode) {
        [ lines[highlightIndex], lines[highlightIndex - 1] ] = [ lines[highlightIndex - 1], lines[highlightIndex] ]
      }
      highlightIndex--
    } else if (str === 'v') {
      moveMode = !moveMode
    } else if (str === 'a') {
      inputMode = true
    } else if (str === 'd') {
      lines.splice(highlightIndex, 1)
      if (highlightIndex >= lines.length) {
        highlightIndex = lines.length - 1
      }
    }
    if (!inputMode) {
      renderContent(lines, highlightIndex, moveMode);
    } else {
      renderInputMode()
    }

  });
}

captureKeyPress()