Within the following code snippet, I am utilizing a service (Angular) to extract text using a fileReader and implementing a promise for the asynchronous part. However, I am encountering an issue that appears to be related to scope, which is causing confusion. In my component, I have defined an instance variable: myDoc : docWrapperClass.
Essentially, when the file reader successfully extracts the text, I intend to assign the results to this local variable. All aspects work correctly until the point at which I attempt the assignment, like so: this.myDoc = docContents after the promise resolves (currently commented out).
The problem arises when the statement remains uncommented, resulting in a compiler error message: Type '{}' is not assignable to type docWrapperClass: fileName.
There is indeed a property on the docWrapperClass named fileName; however, I am uncertain as to what the {} signifies. Consequently, I have disabled the assignment and then placed a breakpoint on the console.log statement within the then() block. Upon typing "this" into the console, I receive 'undefined', which is extremely perplexing. I would anticipate "this" to at least be a function. Therefore, my query is: How can I effectively assign the docWrapperClass returned from the promise to the instance variable?
export class myDocComponent implements OnInit {
constructor(private fileReaderService: ReadLocalFileService,
private textExtractor: TextExtractorServiceService) { }
ngOnInit() { }
docWords: string[] = [];
myDoc: docWrapperClass = null;
selectFile(event: any) {
console.log("Debug");
this.fileReaderService.readFile(event.target.files)
.then((docContents) => {
console.log("DocContents: " + docContents);
//this.myDoc = docContents;
});
}
}