webpack配置反向代理

devServer: {
        contentBase: path.resolve(__dirname, "../dev"),
        compress: true,
        port: ,//本身的端口号
        host: 'localhost',
        proxy: {
            '/api': {
                target: 'http://localhost:3000',//代理到的地址
                changeOrigin: true
            }
        }
    }