javascript - 动态访问变量

Question

假设我正在构建自己的命令行，并且我希望能够访问甚至更改 NodeJS 中通常定义的任何变量。我将在另一个名为 cmd[1] 的变量中定义该变量的名称。经过一段时间的研究，我得出的结论是，不存在保存所有定义变量的全局对象。如何返回另一个变量中描述的变量的数据？这是一个小代码块，解释了我想要实现的目标:

var readline = require('readline');

var rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  prompt: 'CMD> '
});

rl.prompt();

rl.on('line', (line) => {
  var commandl = line.trim();
  var cmd = commandl.split(' ');

  switch(cmd[0]) {
    case 'vr':
      //here i'd like to log the variable which name is in cmd[1]. if there was a global object i would assume i could just global[cmd[1]].
      break;
    case 'spit':
      //here i'd like to log an object with every defined variables and its live changes
      break;
    default:
      console.log(`${line.trim()}: command not found`);
      break;
  }
  rl.prompt();
}).on('close', () => {
  process.exit(0);
});

必须有一个解决方案。

Answer 1

为什么不能创建一个商店并使用它？

store.js

// store.js 
module.exports = {}

app.js

// app.js
var store = require('./store');
var readline = require('readline');

var rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  prompt: 'CMD> '
});

rl.prompt();

rl.on('line', (line) => {
  var commandl = line.trim();
  var cmd = commandl.split(' ');

  switch(cmd[0]) {
    case 'vr':
      store.vr = cmd[1];
      //here i'd like to log the variable which name is in cmd[1]. if there was a global object i would assume i could just global[cmd[1]].
      break;
    case 'spit':
      store.spit = '...';'
      break;
    default:
      console.log(`${line.trim()}: command not found`);
      break;
  }
  rl.prompt();
}).on('close', () => {
  process.exit(0);
});

other.js

// other.js
var store = require('./store');

console.log(store.vr);

虽然您可以使用global，但建议使用此方法，因为您可以轻松模拟商店以进行测试。