React Native 中可能存在未处理的 Promise 拒绝（id：0）

Question

当我声明

async

函数两次时，会发生此错误：

React Native 中可能存在未处理的 Promise 拒绝（id：0）

类别.jsx

import { View, Text } from "react-native";
import Heading from "../../Component/Heading";
import GlobalApi from "../../Utils/GlobalApi";
import React, { useEffect } from "react";

export default function Categories() {
  useEffect(() => {
    getCategories();
  }, []);

  const getCategories = () => {
    GlobalApi.getCategories()
      .then((resp) => {
        console.log("resp", resp.categories);
      });
  };

  return (
    <View>
      <Heading text={"Categories"} isViewAll={true} />
    </View>
  );
}

API类

import { request, gql } from "graphql-request";

const MASTER_URL =
  "https://api-ap-south-1.hygraph.com/v2/clrud3zbv0zjm01w12p1qw5x8/master";

const getSlider = async () => {
  const query = gql`
    query GetSlider {
      sliders {
        id
        name
        image {
          url
        }
      }
    }
  `;
  const result = await request(MASTER_URL, query);
  return result;
};

const getCategories = async () => {
  const query = gql`
    query GetCategory {
      categories {
        id
        name
        icon {
          url
        }
      }
  `;
  const result = await request(MASTER_URL, query);
  return result;
};

export default {
  getSlider,
  getCategories,
};

我尝试了一切，但无法解决这个问题。我尝试创建新类并调用 API，但仍然收到该错误或警告。

Answer 1

getSlider

和

getCategories

函数都返回一个 Promise 对象，除了活动的挂起状态之外，Promise 只能解决或拒绝。您的代码只需要添加处理被拒绝的 Promise 或 Promise 链执行期间是否抛出任何异常。

const getCategories = () => {
  GlobalApi.getCategories()
    .then((resp) => {
      console.log("resp", resp.categories);
    })
    .catch(error => {
      // catch and handle/ignore/etc any rejected Promise or thrown error
    });
};

或用 

async/await

 转换为 

try/catch

const getCategories = async () => {
  try {
    const resp = await GlobalApi.getCategories();
    console.log("resp", resp.categories);
  } catch(error) {
    // catch and handle/ignore/etc any rejected Promise or thrown error
  };
};