Typescript — weird behavior of imported defined JS types:

Question

I am having headaches trying to bring in an auto-generated java-script library into typescript...

I packed the java-script library and d.ts file into a npm package; and installed the npm package, and the typings modules in the host typescript environment; imported the defined classes in ts file

I have got something very weird:

"Sender" is an imported class in the following statement:

let sender: Sender = <Sender>cont.content(new Sender());

the typescript compiler reported "TS2304: Cannot find the name "Sender" with the type definition and casting; whereas the "new Sender()" is fine.

I posted the code snippets below for a better understanding. I had excerpted them for clearance

the js lib

/**
 * @constructor
 */
function Exce() { ...}

Exce.getRootAsExce = function(bb, obj) { ...};

Exce.prototype.text = function(optionalEncoding) {...};

...


/**
 * @constructor
 */
function Promp() { ...}

Promp.getRootAsPromp = function(bb, obj) {...};

Promp.prototype.text = function(optionalEncoding) {...};

...

/**
 * @constructor
 */
function Sender() {...}

Sender.getRootAsSender = function(bb, obj) {...};

Sender.prototype.count = function() {...};

...

/**
 * @constructor
 */
function Bucket() {...}

Bucket.getRootAsBucket = function(bb, obj) {...};

Bucket.prototype.content = function(obj) {...};

...

this.Exce = Exce;

this.Promp = Promp;

this.Sender = Sender;

this.Bucket = Bucket;

...

the .ts file (the d.ts file is the same and acquired from .ts by tsc command

    ...
    export interface Buc_S {
        new (): Buc_I;
        (): Buc_I;

        getRootAsBucket (bb:any, obj:any):any;
        ...
    }
    export interface Buc_I {

        contentType ():Post;
        content (obj:any):any;
    }
    export var Bucket: Buc_S;

    export interface Sen_S {
        new (): Sen_I;
        (): Sen_I;

        getRootAsSender (bb:any, obj:any):any;
    }
    export interface Sen_I {

        count(): number;
       ...
    }
    export var Sender: Sen_S;

    export interface Pro_S {
        new (): Pro_I;
        (): Pro_I;

        getRootAsPromp (bb:any, obj:any):any;
    }
    export interface Pro_I {
        text (optionalEncoding: any): any;
    }
    export var Promp: Pro_S;

    export interface Exc_S {
        new (): Exc_I;
        (): Exc_I;

        getRootAsExce (bb:any, obj:any):any;
    }
    export interface Exc_I {
        text (optionalEncoding: any): any;
    }
    export var Exce: Exc_S;

the typescript host file

import {TransSender} from "./transSender";

import {Bucket, Post,Sender, Promp,Exce} from "fbsj";

export class Decoder{

    public static extractSender (bucket: string):boolean{
        let abs: Bucket = new Bucket();
        let buf = flatbuffers.ByteBuffer(libbase64.decode(bucket));
        let cont = Bucket.getRootAsBucket(buf, Bucket);
        TransSender._type = cont.contentType();
        if(TransSender._type == Post.Sender){
            let sender: Sender = <Sender>cont.content(new Sender());
            TransSender.setter(sender.count(), sender.pushed(), sender.read(), sender.saved(), sender.rated(), sender.followed(), sender.blocked(), sender.forwarded());

        } else if(TransSender._type == Post.Promp){
            TransSender._prompt = (<Promp>cont(new Promp())).text();

        } else if (TransSender._type == Post.Exce){
            TransSender._exception = (<Exce>cont(new Exce())).text();
        }
    }

}

the reported errors

Error:(24, 18) TS2304: Cannot find name 'Bucket'.
Error:(29, 25) TS2304: Cannot find name 'Sender'.
Error:(29, 35) TS2304: Cannot find name 'Sender'.
Error:(33, 37) TS2304: Cannot find name 'Promp'.
Error:(36, 40) TS2304: Cannot find name 'Exce'.

the "Post" is an enum, and worked as expected.

by the way, the first error on "Bucket" had been generated by the statement: let abs: Bucket = new Bucket(); — George Wang
You don't have a type Sender. You have a variable Sender of type Sen_S. In regards to "auto-generated java-script" What does this mean? Is it that you wrote it in typescript and generated the javascript? If so, why do you have interfaces representing classes? — chrisbajorin
to your question "auto-generated js" , it is actually the flatbuffer which is binary communication protocol, that takes in schema, and churns out code lib in various languages, of which js is one of the them. unfortunately , ts is not supported at this moment — George Wang

George Wang George Wang · Accepted Answer · 2016-06-23T02:08:52

thanks to comment from cdbajorin,

I changed the definition style of "Sender" (similar to other...) as the following:

export interface Sender {
    new (): Sender;
    (): Sender;

    getRootAsSender (bb:any, obj:any):any;

    count(): number;
   ...
}
export declare let Sender: Sender;

and it seems working,

cheers

Typescript — weird behavior of imported defined JS types:

1 Answers