Angular 7：类型“void[]”不可分配给类型

Question

I need to populate document object of the following type. I am using Angular 7 typescript. I am getting error Type 'void[]' is not assignable to type 'IDocumentDetails[]

export interface IDocumentUpload {
    fileDropEntry: NgxFileDropEntry;
    name: string;
    selectedDocumentItem: { 'Id': number; 'Name': string; }
    selectedDate: Date;

}

    export interface IDocumentDetails {
        name: string;
        file: any;
        documentTypeId: number;
        documentDate: Date;
    }


    export interface IDocuments {
        managerStrategyId: number;
        documentDetails: IDocumentDetails[];
    }

    documents: IDocuments;
    public files: IDocumentUpload[] = [];

I am getting error at this line of code

const documents: IDocumentDetails[] = this.files.map(doc =>

Code

const documents: IDocumentDetails[] = this.files.map(doc => {
                return  

                     [{ 
                        file: doc.fileDropEntry.fileEntry,
                        documentTypeId: doc.selectedDocumentItem.Id,
                        name: doc.name,
                        documentDate: doc.selectedDate
                    }];

            });

            this.documents = {managerStrategyId : 0, documentDetails: null};
            this.documents.managerStrategyId =  this.ManagerStrategyId;
            this.documents.documentDetails = documents;

Answer 1

Updated the answer just try if its working?

const documents: IDocumentDetails[] = this.files.map((doc) => {
                return { 
                        file: doc.fileDropEntry.fileEntry,
                        documentTypeId: doc.selectedDocumentItem.Id,
                        name: doc.name,
                        documentDate: doc.selectedDate
                    };

            });

            this.documents = {managerStrategyId : 0, documentDetails: null};
            this.documents.managerStrategyId =  this.ManagerStrategyId;
            this.documents.documentDetails = documents;

Answer 2

Since your return statement is not followed by a bracket '(', you are returning nothing. try to place the curly bracket in the same line with the 'return' word.

Alos, like @JSON Derolu said, your .map function needs to return an object, not an array, so remove the square bracket.

try this code:

const documents: IDocumentDetails[] = this.files.map(doc => {
  return { // notice just a curly bracket, and in the same line with 'return'
    file: doc.fileDropEntry.fileEntry,
    documentTypeId: doc.selectedDocumentItem.Id,
    name: doc.name,
    documentDate: doc.selectedDate
  };
});

Answer 3

Your const documents is of type IDocumentDetails[] so you will need to return an object of type IDocumentDetails in your map function.

Try this.

const documents: IDocumentDetails[] = this.files.map((doc: IDocumentUpload): IDocumentDetails => {
  return {
    file: doc.fileDropEntry.fileEntry,
    documentTypeId: doc.selectedDocumentItem.Id,
    name: doc.name,
    documentDate: doc.selectedDate
  };
});

I have made your code more strongly typed by specifying the data types. Here the doc parameter in the map function is of type IDocumentUpload and the return type of the function is IDocumentDetails which the object you are returning in your map function.

Answer 4

Try to cast your response like that:

const documents: IDocumentDetails[] = this.files.map(doc => {
            return 
                 [{ 
                    file: doc.fileDropEntry.fileEntry,
                    documentTypeId: doc.selectedDocumentItem.Id,
                    name: doc.name,
                    documentDate: doc.selectedDate
                }] as IDocumentDetails[];
        });