node.js TypeError: path must be absolute or specified root to res.sendFile [failed to parse JSON]

如何解决node.js TypeError: path must be absolute or specified root to res.sendFile [failed to parse JSON]

错误很明显，您需要指定一个绝对（而不是相对）路径和/或root在 .config 对象中设置res.sendFile()。例子：

// assuming index.html is in the same directory as this script

res.sendFile(__dirname + '/index.html');

或指定一个根（用作第一个参数的基本路径res.sendFile()：

res.sendFile('index.html', { root: __dirname });

当您传递用户生成的文件路径时，指定root路径更有用，该路径可能包含格式错误/恶意的部分，例如..（例如../../../../../../etc/passwd）。设置root路径可防止此类恶意路径被用于访问该基本路径之外的文件。

解决方法

[添加] 所以我的下一个问题是当我尝试添加新的依赖项时（npm install –save socket.io）。JSON
文件也是有效的。我收到此错误：无法解析 json

npm ERR! Unexpected string
npm ERR! File: /Users/John/package.json
npm ERR! Failed to parse package.json data.
npm ERR! package.json must be actual JSON,not just JavaScript.
npm ERR! 
npm ERR! This is not a bug in npm.
npm ERR! Tell the package author to fix their package.json file. JSON.parse

所以我一直在试图弄清楚为什么这个错误一直在返回。所有文件（HTML、JSON、JS）都在我桌面上的同一个文件夹中。我正在使用 node.js 和
socket.io

这是我的 JS 文件：

var app = require('express')();
var http = require('http').Server(app);

app.get('/',function(req,res){
  res.sendFile('index.html');
});

http.listen(3000,function(){
    console.log('listening on : 3000');
});

这是返回的内容：

MacBook-Pro:~ John$ node /Users/John/Desktop/Chatapp/index.js 
listening on : 3000
TypeError: path must be absolute or specify root to res.sendFile
    at ServerResponse.sendFile (/Users/John/node_modules/express/lib/response.js:389:11)
    at /Users/John/Desktop/Chatapp/index.js:5:7
    at Layer.handle [as handle_request] (/Users/John/node_modules/express/lib/router/layer.js:76:5)
    at next (/Users/John/node_modules/express/lib/router/route.js:100:13)
    at Route.dispatch (/Users/John/node_modules/express/lib/router/route.js:81:3)
    at Layer.handle [as handle_request] (/Users/John/node_modules/express/lib/router/layer.js:76:5)
    at /Users/John/node_modules/express/lib/router/index.js:234:24
    at Function.proto.process_params (/Users/John/node_modules/express/lib/router/index.js:312:12)
    at /Users/John/node_modules/express/lib/router/index.js:228:12
    at Function.match_layer (/Users/John/node_modules/express/lib/router/index.js:295:3)
TypeError: path must be absolute or specify root to res.sendFile
    at ServerResponse.sendFile (/Users/John/node_modules/express/lib/response.js:389:11)
    at /Users/John/Desktop/Chatapp/index.js:5:7
    at Layer.handle [as handle_request] (/Users/John/node_modules/express/lib/router/layer.js:76:5)
    at next (/Users/John/node_modules/express/lib/router/route.js:100:13)
    at Route.dispatch (/Users/John/node_modules/express/lib/router/route.js:81:3)
    at Layer.handle [as handle_request] (/Users/John/node_modules/express/lib/router/layer.js:76:5)
    at /Users/John/node_modules/express/lib/router/index.js:234:24
    at Function.proto.process_params (/Users/John/node_modules/express/lib/router/index.js:312:12)
    at /Users/John/node_modules/express/lib/router/index.js:228:12
    at Function.match_layer (/Users/John/node_modules/express/lib/router/index.js:295:3)