Question

我收到了这个错误：

SP-web部件-工作台-assembly_en-us_b854c4b93cc10a271230fd4a9e7b2b9b.js：661 未捕获（承诺）TypeError：已经读过在t.e.json（sp-webpart-workbench-assembly_en-us_b854c4b93cc10a271230fd4a9e7b2b9b.js：661）在ListItemFactory.ts：81 在

抛出错误的代码行在这里：

 .then((response: SPHttpClientResponse): Promise<{ value: IAnnouncementListItem[] }> => {
                    return response.json();
                })

整个班级是：

import { SPHttpClient, SPHttpClientResponse } from "@microsoft/sp-http";
import { IWebPartContext } from "@microsoft/sp-webpart-base";
import { IListItem} from "./models/IListItem";
import { IFactory } from "./IFactory";
import { INewsListItem } from "./models/INewsListItem";
import { IDirectoryListItem } from "./models/IDirectoryListItem";
import { IAnnouncementListItem } from "./models/IAnnouncementListItem";

export class ListItemFactory implements IFactory {
    // private _listItems: IListItem[];
    public getItems(requester: SPHttpClient, siteUrl: string, listName: string): Promise<any[]> {
        switch(listName) {
            case "GenericList":
                let items: IListItem[];
                // tslint:disable-next-line:max-line-length
                return requester.get(`${siteUrl}/_api/web/lists/getbytitle('${listName}')/items?$select=Title,Id,Modified,Created,Author/Title,Editor/Title&$expand=Author,Editor`,
                SPHttpClient.configurations.v1,
                {
                    headers: {
                        "Accept": "application/json;odata=nometadata",
                        "odata-version": ""
                    }
                })
                .then((response: SPHttpClientResponse): Promise<{ value: IListItem[] }> => {
                    return response.json();
                })
                .then((json: { value: IListItem[] }) => {
                    console.log(JSON.stringify(json.value));
                    return items=json.value.map((v,i)=>(
                        {
                            // key: v.id,
                            id: v.Id,
                            title: v.Title,
                            created: v.Created,
                            createdby: v.Author.Title,
                            modified: v.Modified,
                            modifiedby: v.Editor.Title
                        }
                    ));
                });
            case "News":
                let newsitems: INewsListItem[];
                // tslint:disable-next-line:max-line-length
                return requester.get(`${siteUrl}/_api/web/lists/getbytitle('${listName}')/items?$select=Title,Id,Modified,Created,newsheader,newsbody,expiryDate,Author/Title,Editor/Title&$expand=Author,Editor`,
                SPHttpClient.configurations.v1,
                {
                    headers: {
                        "Accept": "application/json;odata=nometadata",
                        "odata-version": ""
                    }
                })
                .then((response: SPHttpClientResponse): Promise<{ value: INewsListItem[] }> => {
                    return response.json();
                })
                .then((json: { value: INewsListItem[] }) => {
                    return newsitems=json.value.map((v,i)=>(
                        { 
                            id: v.Id,
                            title: v.Title,
                            created: v.Created,
                            createdby: v.Author.Title,
                            modified: v.Modified,
                            modifiedby: v.Editor.Title,
                            newsheader: v.newsheader,
                            newsbody: v.newsbody,
                            expiryDate: v.expiryDate
                        }
                    ));
                });
            case "Announcements":
                let announcementitems: IAnnouncementListItem[];
                return requester.get(`${siteUrl}/_api/web/lists/getbytitle('${listName}')/items?$select=Title,Id,Modified,Created,announcementBody,expiryDate,Author/Title,Editor/Title&$expand=Author,Editor`,
                SPHttpClient.configurations.v1,
                {
                    headers: {
                        "Accept": "application/json;odata=nometadata",
                        "odata-version": ""
                    }
                })
                .then((response: SPHttpClientResponse): Promise<{ value: IAnnouncementListItem[] }> => {
                    return response.json();
                })
                .then((json: { value: IAnnouncementListItem[] }) => {
                    return announcementitems=json.value.map((v,i)=>(
                        { 
                            id: v.Id,
                            title: v.Title,
                            created: v.Created,
                            createdby: v.Author.Title,
                            modified: v.Modified,
                            modifiedby: v.Editor.Title,
                            announcementBody: v.announcementBody,
                            expiryDate: v.expiryDate
                        }
                    ));
                });
            case "Directory":
                let directoryitems: IDirectoryListItem[];
                return requester.get(`${siteUrl}/_api/web/lists/getbytitle('${listName}')/items?$select=Title,Id,Modified,Created,firstName,lastName,mobileNumber,internalNumber,Author/Title,Editor/Title&$expand=Author,Editor`,
                SPHttpClient.configurations.v1,
                {
                    headers: {
                        "Accept": "application/json;odata=nometadata",
                        "odata-version": ""
                    }
                })
                .then((response: SPHttpClientResponse): Promise<{ value: IDirectoryListItem[] }> => {
                    return response.json();
                })
                .then((json: { value: IDirectoryListItem[] }) => {
                    return directoryitems=json.value.map((v,i)=>(
                        {
                            id: v.Id,
                            title: v.Title,
                            created: v.Created,
                            createdby: v.Author.Title,
                            modified: v.Modified,
                            modifiedby: v.Editor.Title,
                            firstName: v.firstName,
                            lastName: v.lastName,
                            mobileNumber: v.mobileNumber,
                            internalNumber: v.internalNumber
                        }
                    ));
                });
            default:
                break;
            }
      }
}

请注意，这是一个带有ReactJS的Sharepoint webpart，用户从属性窗格中选择一个列表，第一次呈现webpart时，它从GenericList中获取默认值，然后用户可以选择另一个列表如公告，当用户选择不同的列表时，我会收到错误

我在这里错过了什么？

Answer 1

您已拨打response.json()两次。 fetch()中不允许这样做。

如果您想知道响应中的内容，请使用text()自行阅读和解析，以防它无效json。（您也可以只使用text()一次，但如果JSON.parse()失败，您仍然知道原因。）这可能不是您的问题。您只是阅读了两次回复主体，并且这是一个带fetch()的nono。

在控制台中重现JS：

fetch('/').then(rsp => {
  rsp.json().then(console.log); // << invalid json, probably
  rsp.json().then(console.log); // << already read
})

（一个错误是＆＃39;无效的json＆＃39;，但这不相关。）其他错误将会被阅读＆＃39;。

原因背后的原因是你的lib。 requester.get可能会读取回复，因此您无法做到。也许SPHttpClientResponse有一些其他方法/属性来阅读它。

Answer 2

不要忘记在每个案例结束时使用break;，而是在第一次案例结束后运行所有案例。

未捕获（承诺）TypeError：已经读过

2 个答案: