收到来自。Then()的承诺{&lt；Pending&gt；}-前端问题

Receiving Promise {lt;pendinggt;} back from .then()(收到来自。Then()的承诺{lt；Pendinggt；})

本文介绍了收到来自。Then()的承诺{&lt；Pending&gt；}的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我在api.js中有一个API调用：数据-lang="js"数据-隐藏="假"数据-控制台="真"数据-巴贝尔="假">

 export const getGraphData = (domain, userId, testId) => {
   return axios({
     url: `${domain}/api/${c.embedConfig.apiVersion}/member/${userId}/utests/${testId}`,
     method: 'get',
   });
 };

我有一个接受该数据并对其进行转换的反应帮助器。数据-lang="js"数据-隐藏="假"数据-控制台="真"数据-巴贝尔="假">

import { getGraphData } from './api';

const dataObj = (domain, userId, testId) => {

  const steps = getGraphData(domain, userId, testId)
  .then((result) => {
    return result.attributes;
  });

  console.log(steps);

  // const steps = test.get('steps');
  const expr = /select/;

  // build array of steps that we have results in
  const resultsSteps = [];

  steps.forEach((step) => {
    // check for types that contain 'select', and add them to array
    if (expr.test(step.get('type'))) {
      resultsSteps.push(step);
    }
  });

  const newResultsSteps = [];

  resultsSteps.forEach((item, i) => {
    const newMapStep = new Map();
    const itemDescription = item.get('description');
    const itemId = item.get('id');
    const itemOptions = item.get('options');
    const itemAnswers = item.get('userAnswers');
    const newOptArray = [];
    itemOptions.forEach((element) => {
      const optionsMap = new Map();
      let elemName = element.get('value');
      if (!element.get('value')) { elemName = element.get('caption'); }
      const elemPosition = element.get('position');
      const elemCount = element.get('count');

      optionsMap.name = elemName;
      optionsMap.position = elemPosition;
      optionsMap.value = elemCount;
      newOptArray.push(optionsMap);
    });
    newMapStep.chartType = 'horizontalBar';
    newMapStep.description = itemDescription;
    newMapStep.featured = 'false';
    newMapStep.detailUrl = '';
    newMapStep.featuredStepIndex = i + 1;
    newMapStep.id = itemId;
    newMapStep.isValid = 'false';
    newMapStep.type = 'results';
    const listForNewOptArray = List(newOptArray);
    newMapStep.data = listForNewOptArray;
    newMapStep.userAnswers = itemAnswers;
    newResultsSteps.push(newMapStep);
  });

  return newResultsSteps;
};

export default dataObj;

问题是steps，在.then()之外登录时会返回Promise {<pending>}。如果我在.then()中记录results.attributes，我会看到数据已完全返回。

推荐答案

您需要等待，直到解决您的异步呼叫。您可以通过链接到另一个then：

来完成此操作

getGraphData(domain, userId, testId)
  .then((result) => {
    return result.attributes;
  })
  .then(steps => {
     // put the rest of your method here
  });

如果您的平台支持async/await，您还可以查看async/await，这将使代码更接近您的原始

const steps = await getGraphData(domain, userId, testId)
  .then((result) => {
    return result.attributes;
  });

// can use steps here

这篇关于收到来自。Then()的承诺{&lt；Pending&gt；}的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！