editor.js

import fs from 'fs';
import mktemp from 'mktemp';
import { spawn } from 'child_process';

export default class Editor {
  constructor(editor) {
    this.editor = editor || process.env.EDITOR || 'vi';
  }

  writeFile(file, content) {
    return new Promise((resolve, reject) => {
      fs.writeFile(file, content, err => {
        if (err) {
          reject(err);
        } else {
          resolve(file);
        }
      });
    });
  }

  readFile(file) {
    return new Promise((resolve, reject) => {
      fs.readFile(file, (err, content) => {
        if (err) {
          reject(err);
        } else {
          resolve({file, content});
        }
      });
    });
  }

  delFile(file) {
    return new Promise((resolve, reject) => {
      fs.unlink(file, err => {
        if (err) {
          reject(err);
        } else {
          resolve(file);
        }
      });
    });
  }

  edit(file) {
    return new Promise((resolve, reject) => {
      spawn(this.editor, [file], {stdio: 'inherit'}).on('exit', code => {
        if (code === 0) {
          resolve(file);
        } else {
          reject(new Error(`${editor} had non zero exit code: ${code}`));
        }
      });
    });
  }

  editContent(origContent) {
    return mktemp.createFile('XXXXX.txt')
      .then(file => this.writeFile(file, origContent))
      .then(file => this.edit(file))
      .then(file => this.readFile(file))
      .then(({file, content}) => this.delFile(file).then(() => content));
  }
}