NodeJS Promises 返回 Pending

Question

上下文：我正在尝试使用 jest 和 supertest 为我正在编写的 MongoDB 应用程序设置测试

目的：将一个值 return 从 postArticleByAPI 函数赋值给常量 id。

问题：returning Promise { <pending> }

我尝试过的：

Promise.resolve(postArticleByAPI) 导致同样的问题。
链接 .then((res) => {console.log(res}) 结果为 undefined.

我想我从根本上不理解承诺，也就是如何在承诺之外为 return 赋值。这可能吗？有人有什么建议吗？

const articleData = {title: 'Hello123', doi: '123', journal: 'Facebook'};

/**
 * Posts an article through the API
 * @param {Object} article - the article objection containing dummy data
 * @return {string} request - the article id stored in the database
**/
async function postArticleByAPI(article) {
  await request(app)
      .post('/api/articles')
      .send(article)
      .expect(200)
      .then((response) => {
        expect(response.body.title).toBe(article.title);
        expect(response.body.doi).toBe(article.doi);
        expect(response.body.journal).toBe(article.journal);
        expect(response.body.id).toBeTruthy();
        return response.body.id;
      });
}


describe('Test POST through API', () => {
  test('It should response the POST method /api/articles', () => {
    const id = postArticleByAPI(articleData);
    console.log(id);
  });
});

Answer 1

确实postArticleByAPIreturn是Promise而且在您记录时它还没有解决。你应该这样写：

describe('Test POST through API', () => {
  test('It should response the POST method /api/articles', async () => {
    const id = await postArticleByAPI(articleData);
    console.log(id);
  });
});

也不要忘记 return 来自 postArticleByAPI 的承诺：

function postArticleByAPI(article) {
  return request(app)
      .post('/api/articles')
      .send(article)
      .expect(200)
      .then((response) => {
        expect(response.body.title).toBe(article.title);
        expect(response.body.doi).toBe(article.doi);
        expect(response.body.journal).toBe(article.journal);
        expect(response.body.id).toBeTruthy();
        return response.body.id;
      });
}

如果要使用async和await，则不应使用.then-

async function postArticleByAPI(article) {
  const response =
    await request(app)
      .post('/api/articles')
      .send(article)
      .expect(200)

  expect(response.body.title).toBe(article.title);
  expect(response.body.doi).toBe(article.doi);
  expect(response.body.journal).toBe(article.journal);
  expect(response.body.id).toBeTruthy();
  return response.body.id;
}

NodeJS Promises 返回 Pending

NodeJS Promises returning Pending

javascript

node.js

promise

es6-promise