你也可以添加一个中间件来添加CORS头，像这样就可以了:

/**
 * Adds CORS headers to the response
 *
 * {@link https://en.wikipedia.org/wiki/Cross-origin_resource_sharing}
 * {@link http://expressjs.com/en/4x/api.html#res.set}
 * @param {object} request the Request object
 * @param {object} response the Response object
 * @param {function} next function to continue execution
 * @returns {void}
 * @example
 * <code>
 * const express = require('express');
 * const corsHeaders = require('./middleware/cors-headers');
 *
 * const app = express();
 * app.use(corsHeaders);
 * </code>
 */
module.exports = (request, response, next) => {
    // http://expressjs.com/en/4x/api.html#res.set
    response.set({
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Methods': 'DELETE,GET,PATCH,POST,PUT',
        'Access-Control-Allow-Headers': 'Content-Type,Authorization'
    });

    // intercept OPTIONS method
    if(request.method === 'OPTIONS') {
        response.send(200);
    } else {
        next();
    }
};

你也可以添加一个中间件来添加CORS头，像这样就可以了:

/**
 * Adds CORS headers to the response
 *
 * {@link https://en.wikipedia.org/wiki/Cross-origin_resource_sharing}
 * {@link http://expressjs.com/en/4x/api.html#res.set}
 * @param {object} request the Request object
 * @param {object} response the Response object
 * @param {function} next function to continue execution
 * @returns {void}
 * @example
 * <code>
 * const express = require('express');
 * const corsHeaders = require('./middleware/cors-headers');
 *
 * const app = express();
 * app.use(corsHeaders);
 * </code>
 */
module.exports = (request, response, next) => {
    // http://expressjs.com/en/4x/api.html#res.set
    response.set({
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Methods': 'DELETE,GET,PATCH,POST,PUT',
        'Access-Control-Allow-Headers': 'Content-Type,Authorization'
    });

    // intercept OPTIONS method
    if(request.method === 'OPTIONS') {
        response.send(200);
    } else {
        next();
    }
};

这太烦人了。

好的，如果有人仍然有问题或只是不想添加另一个库。你所要做的就是把这个中间件代码行放在你的路由之前。

歌珥的例子

app.use((req, res, next) => {
    res.append('Access-Control-Allow-Origin', ['*']);
    res.append('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
    res.append('Access-Control-Allow-Headers', 'Content-Type');
    next();
});

// Express routes
app.get('/api/examples', (req, res)=> {...});

服务。使用(函数(req, res, next) { res.header(“Access-Control-Allow-Origin”、“*”); res.header(“Access-Control-Allow-Methods”、“获取、头选择、POST、PUT "); res.header("Access-Control-Allow-Headers"， "Origin, x - request - with, Content-Type, Accept, Authorization"); next (); })；

@klode的答案是正确的。

但是，您应该设置另一个响应标头以使其他人可以访问您的标头。

例子:

首先，在响应头中添加“page-size”

response.set('page-size', 20);

然后，你所需要做的就是暴露你的头文件

response.set('Access-Control-Expose-Headers', 'page-size')

您可以使用cors来做到这一点。cors将处理您的cors回复

var cors = require('cors')

app.use(cors());