小编a8h*_*hok的帖子

我有一个对象数组，我必须按index属性上的重复值将其拆分。对于像下一个这样的对象示例数组：

[
  {index: 0, value: 3},
  {index: 0, value: 3},
  {index: 0, value: 3},
  {index: 1, value: 3},
  {index: 1, value: 3},
  {index: 2, value: 3},
  {index: 2, value: 3}
]

预期结果应该是：

{
  0: [
    {index: 0, value: 3},
    {index: 0, value: 3},
    {index: 0, value: 3}
  ],
  1: [
    {index: 1, value: 3},
    {index: 1, value: 3}          
  ],
  2: [
    {index: 2, value: 3},
    {index: 2, value: 3}
  ]
}

var express = require('express');
var app = express();
app.get('/', function(req, res){
    res.send('hello world');
});
app.listen(3000);

我收到以下错误.

> D:\nodejs\mynode\index.js:2  
> var app=express();
    ^
ReferenceError: express is not defined
    at Object.<anonymous> (D:\nodejs\mynode\index.js:2:9)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)
    at startup (node.js:119:16)
    at node.js:902:3