SharePoint 框架和 TypeScript &等待所有承诺完成，然后再返回客户端

Question

我有一个关于在将值返回给客户端之前等待承诺解决的问题。

我正在使用 SharePoint 框架从我的配置列表中获取列表和文档库名称的集合，然后使用这些名称(列表和文档库名称(回调到 SharePoint 以检索每个列表和文档库的列表项。

下面提供了我的代码，用于检索我将用于检索列表项的列表和文档库的名称：

private _getListData(): Promise<ISPLists> {
let listName:string = "SPListDisplayUIConfig";
let currentUrl      = this.context.pageContext.web.absoluteUrl + `/_api/web/lists/GetByTitle('`+listName+`')/Items`;
var formatedResponse: ISPLists = { value: [] };
return this.context.spHttpClient.get(currentUrl, SPHttpClient.configurations.v1)
.then((response: SPHttpClientResponse) => {
//Extract the response.json object.
return response.json().then((responseFormated: any) => {
//Evaluate the response.               
responseFormated.value.map((object: any, i: number) =>{
var listItems: ListObjects = { value: [] };
var spListItem: ISPList = {
Id: object['ID'],
Title: object['Title'],
DisplayListTitle: object['DisplayListTitle'],
RowCount: object['RowCount'],
SortOrder: object['SortOrder'],
ShowOnHomePage: object['ShowOnHomePage'],
ListType: '',
ListItems:  listItems
};
formatedResponse.value.push(spListItem); 
});
//Create a local list and store all the this._getListItems(Title) calls into the array, then pass the local array into the Promise.all method to execute each
//method. In the return result (then), extract each list item and store into the spListItem.ListItem property.
let promisesMethods:any = [];
formatedResponse.value.forEach((item:ISPList) => {
let listName:string = item.Title;
promisesMethods.push(this._getListItems(listName));
});
Promise.all(promisesMethods).then((result:any) => {
console.log("Here");
});
console.log("Here 1")
return formatedResponse;
})
})
}

this._getListItems 方法检索每个列表名的列表项。

let promisesMethods:any = [];
formatedResponse.value.forEach((item:ISPList) => {
let listName:string = item.Title;
promisesMethods.push(this._getListItems(listName));
});
Promise.all(promisesMethods).then((result:any) => {
console.log("Here");
});
console.log("Here 1")

这是this._getListItems定义：

private _getListItems(ListName: string): Promise<ListObjects>{
let currentUrl = this.context.pageContext.web.absoluteUrl + `/_api/web/lists/GetByTitle('`+ListName+`')/Items`; 
return this.context.spHttpClient.get(currentUrl, SPHttpClient.configurations.v1)
.then((response: SPHttpClientResponse) => {
return response.json().then((responseFormated: any) => {
var formatedResponse: ListObjects = { value: []};  
responseFormated.value.map((object: any, i: number) =>{
var spListItem: ListObject = {
Title: object['Title'],
ItemUrl: "",
ItemType: "",
FileType: "",
Id: object['ID']
};
formatedResponse.value.push(spListItem);
});
return formatedResponse;
})
})
}

在下面的代码中，控制台.log("此处 1"(在控制台.log("此处"(之前调用。在将结果返回给客户端之前，我需要获取每个列表和库的所有列表项。

let promisesMethods:any = [];
formatedResponse.value.forEach((item:ISPList) => {
let listName:string = item.Title;
promisesMethods.push(this._getListItems(listName));
});
Promise.all(promisesMethods).then((result:any) => {
console.log("Here");
});
console.log("Here 1")
return formatedResponse;

谢谢

Answer 1

只需在then块中继续您的代码，然后在外部块中，将与该then块对应的 promise 返回给调用方。 像这样：

private _getListData(): Promise<ISPLists> {
let listName:string = "SPListDisplayUIConfig";
let currentUrl      = this.context.pageContext.web.absoluteUrl + `/_api/web/lists/GetByTitle('`+listName+`')/Items`;
var formatedResponse: ISPLists = { value: [] };
return this.context.spHttpClient.get(currentUrl, SPHttpClient.configurations.v1)
.then((response: SPHttpClientResponse) => {
//Extract the response.json object.
return response.json().then((responseFormated: any) => {
//Evaluate the response.               
responseFormated.value.map((object: any, i: number) =>{
var listItems: ListObjects = { value: [] };
var spListItem: ISPList = {
Id: object['ID'],
Title: object['Title'],
DisplayListTitle: object['DisplayListTitle'],
RowCount: object['RowCount'],
SortOrder: object['SortOrder'],
ShowOnHomePage: object['ShowOnHomePage'],
ListType: '',
ListItems:  listItems
};
formatedResponse.value.push(spListItem); 
});
//Create a local list and store all the this._getListItems(Title) calls into the array, then pass the local array into the Promise.all method to execute each
//method. In the return result (then), extract each list item and store into the spListItem.ListItem property.
let promisesMethods:any = [];
formatedResponse.value.forEach((item:ISPList) => {
let listName:string = item.Title;
promisesMethods.push(this._getListItems(listName));
});
return Promise.all(promisesMethods).then((result:any) => {
//             ^^^^^^
console.log("Here");
// Any more necessary processing
return /* whatever result you want */;
});
})
})
}