对于上传表单编码的POST请求，我建议使用FormData对象。

示例代码:

var params = {
    userName: 'test@gmail.com',
    password: 'Password!',
    grant_type: 'password'
};

var formData = new FormData();

for (var k in params) {
    formData.append(k, params[k]);
}

var request = {
    method: 'POST',
    headers: headers,
    body: formData
};

fetch(url, request);

使用URLSearchParams

https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams

var data = new URLSearchParams();
data.append('userName', 'test@gmail.com');
data.append('password', 'Password');
data.append('grant_type', 'password');

只使用

import  qs from "qs";
 let data = {
        'profileId': this.props.screenProps[0],
        'accountId': this.props.screenProps[1],
        'accessToken': this.props.screenProps[2],
        'itemId': this.itemId
    };
    return axios.post(METHOD_WALL_GET, qs.stringify(data))

var details = {
    'userName': 'test@gmail.com',
    'password': 'Password!',
    'grant_type': 'password'
};

var formBody = [];
for (var property in details) {
  var encodedKey = encodeURIComponent(property);
  var encodedValue = encodeURIComponent(details[property]);
  formBody.push(encodedKey + "=" + encodedValue);
}
formBody = formBody.join("&");

fetch('http://identity.azurewebsites.net' + '/token', {
  method: 'POST',
  headers: {
    'Accept': 'application/json',
    'Content-Type': 'application/x-www-form-urlencoded'
  },
  body: formBody
})

它对我很有帮助，而且没有任何错误

参考资料:https://gist.github.com/milon87/f391e54e64e32e1626235d4dc4d16dc8

在一个简单的函数中包装取回

async function post_www_url_encdoded(url, data) {
    const body = new URLSearchParams();
    for (let key in data) {
        body.append(key, data[key]);
    }
    return await fetch(url, { method: "POST", body });
}

const response = await post_www_url_encdoded("https://example.com/login", {
    "name":"ali",
    "password": "1234"});
if (response.ok){ console.log("posted!"); }

不需要使用jQuery、querystring或手动组装有效负载。URLSearchParams是一种方法，这里是一个最简洁的答案与完整的请求示例:

fetch('https://example.com/login', {
  method: 'POST',
  body: new URLSearchParams({
    param: 'Some value',
    anotherParam: 'Another value'
  })
})
  .then(response => {
    // Do stuff with the response
  });

同样的技术使用async / await。

const login = async () => {
  const response = await fetch('https://example.com/login', {
    method: 'POST',
    body: new URLSearchParams({
      param: 'Some value',
      anotherParam: 'Another value'
    })
  })

  // Do stuff with the response
}

是的，您可以使用Axios或任何其他HTTP客户端库来代替本机获取。