对于Node.js应用程序，在注册我自己的所有路由之前，请在server.js文件中将代码放在下面。它设置所有响应的标题。如果它是预检“ OPTIONS”调用，它也可以优雅地结束响应，并立即将预检响应发送回客户端，而无需通过实际业务逻辑路径向下“继续”(这是一个词吗？)。这是我的server.js文件。突出显示了相关部分，以供Stackoverflow使用。

// server.js

// ==================

// BASE SETUP

// import the packages we need

var express    = require('express');

var app        = express();

var bodyParser = require('body-parser');

var morgan     = require('morgan');

var jwt        = require('jsonwebtoken'); // used to create, sign, and verify tokens

// ====================================================

// configure app to use bodyParser()

// this will let us get the data from a POST

app.use(bodyParser.urlencoded({ extended: true }));

app.use(bodyParser.json());

// Logger

app.use(morgan('dev'));

// -------------------------------------------------------------

// STACKOVERFLOW -- PAY ATTENTION TO THIS NEXT SECTION !!!!!

// -------------------------------------------------------------

//Set CORS header and intercept "OPTIONS" preflight call from AngularJS

var allowCrossDomain = function(req, res, next) {

res.header('Access-Control-Allow-Origin', '*');

res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');

res.header('Access-Control-Allow-Headers', 'Content-Type');

if (req.method === "OPTIONS")

res.send(200);

else

next();

}

// -------------------------------------------------------------

// STACKOVERFLOW -- END OF THIS SECTION, ONE MORE SECTION BELOW

// -------------------------------------------------------------

// =================================================

// ROUTES FOR OUR API

var route1 = require("./routes/route1");

var route2 = require("./routes/route2");

var error404 = require("./routes/error404");

// ======================================================

// REGISTER OUR ROUTES with app

// -------------------------------------------------------------

// STACKOVERFLOW -- PAY ATTENTION TO THIS NEXT SECTION !!!!!

// -------------------------------------------------------------

app.use(allowCrossDomain);

// -------------------------------------------------------------

//  STACKOVERFLOW -- OK THAT IS THE LAST THING.

// -------------------------------------------------------------

app.use("/api/v1/route1/", route1);

app.use("/api/v1/route2/", route2);

app.use('/', error404);

// =================

// START THE SERVER

var port = process.env.PORT || 8080;        // set our port

app.listen(port);

console.log('API Active on port ' + port);