Typescript generating javascript that doesn't work

Question

Node is not happy about something in the Javascript that TypeScript is generating and I can't figure out why. Here is the code

Person.ts:

export module Models {
    export class Person {
        id: number;
        firstName: string;
        lastName: string;

        constructor(f: string, l: string) {
            this.firstName = f;
            this.lastName = l;
        }

        public saySomething(): void {
            console.log("my name is %s %s", this.firstName, this.lastName);
        }
    }
}

Database.ts:

import P = module("Person");

export module Database {
    export class DB {
        public findPerson(id: number): P.Models.Person {
            return new P.Models.Person("a", "b");
        }
    }
}

Test.ts:

var D = require("./DB");
var db = new D.Database.DB();
var p = db.findPerson(123);
p.saySomething();

It compiles fine down in Javascript, but there appears to be something wrong with the DB.js file that is being created. When I try to run Test.js in node I get this:

$node Test.js
DB.js:2
(function (Database) {
^
TypeError: object is not a function
    at Object.<anonymous> (DB.js:2:1)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.require (module.js:362:17)
    at require (module.js:378:17)
    at Object.<anonymous> (Test.js:1:73)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)

It's happening during the import of DB.js. Oddly enough, if I change the findPerson() method to return a string instead of a Person it works fine. It has something to do with creating that Person object.

Here is the Javascript:

(function (Models) {
    var Person = (function () {
        function Person(f, l) {
            this.firstName = f;
            this.lastName = l;
        }
        Person.prototype.saySomething = function () {
            console.log("my name is %s %s", this.firstName, this.lastName);
        };
        return Person;
    })();
    Models.Person = Person;    
})(exports.Models || (exports.Models = {}));


var P = require("./Person")
(function (Database) {
    var DB = (function () {
        function DB() { }
        DB.prototype.findPerson = function (id) {
            return new P.Models.Person("a", "b");
        };
        return DB;
    })();
    Database.DB = DB;    
})(exports.Database || (exports.Database = {}));


var dbx = require("./DB")
var db1 = new dbx.Database.DB();
var p = db1.findPerson(123);
p.saySomething();

Dima Vidmich · Accepted Answer · 2012-11-02 22:27:45Z

5

without semicolon after var P = require("./Person") javascript thinks than next (...) is call of a function. but you seem have it in Database.ts, so Typescript probably loosing some semicolons in compilation.

answered Nov 2, 2012 at 22:27

Dima Vidmich

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3 Comments

d512 Over a year ago

Wow, you're absolutely right. The missing semi-colon in the DB.js file is what is causing the issue. I guess I should file a bug with Microsoft.

Matt Browne Over a year ago

Looks like someone already did; just vote it up: typescript.codeplex.com/workitem/364

Matt Browne Over a year ago

Or maybe that was you, haha...just noticed this answer was from November.

Fenton · Accepted Answer · 2012-11-02 22:45:01Z

0

The main issue is that you are importing a module named Person, where I think you mean to import the Models module that contains a class named Person.

When you are targeting nodejs, or other CommonJS platforms, you omit the module declarations.

You can also take advantage of auto-properties in the constructor.

So you would have Models.ts:

export class Person {
    id: number;

    constructor (public firstName: string, public lastName: string) {

    }

    public saySomething(): void {
        console.log("my name is %s %s", this.firstName, this.lastName);
    }
}

And Database.ts

import models = module("Models");

export class DB {
    public findPerson(id: number): models.Person {
        return new models.Person("a", "b");
    }
}

answered Nov 2, 2012 at 22:45

Fenton

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2 Comments

d512 Over a year ago

Maybe I'm not understanding the concept behind modules correctly, but what I was attempting to do was group related classes together using the module keyword. So I would have the Person, Car, Dog classes under the "Models" module and have Query, Table, Recordset under the "Database" module. Basically using the "module" keyword like a C# namespace. I could do what you're saying, but then I have to put all my model classes in one giant file, which I don't want to do.

Fenton Over a year ago

You can still do something similar in CommonJS - you can use a nested folder structure to have a "./Models/Person" module, a "./Models/Animal" module and so on. The Person.ts and Animal.ts are inherent modules, but you can export your classes from them and they are grouped into the Models namespace.

Mattia Peiretti · Accepted Answer · 2024-01-20 22:36:15Z

0

For me the problem is that I was trying to import a function for file B, in my main file A

File B:

//other stuff

export function doSomething() {
  //....
}

File A:

import {doSomething} from "./fileB";

doSomething()

BUT, above the function doSomething() in fileB, there was an explicit export like this: File B:


function doSomethingElse() {
    // legacy stuff
}

module.exports = doSomethingElse;

export function doSomething() {
  //....
}

Somehow, PHP Storm didn't signal me...

answered Jan 20, 2024 at 22:36

Mattia Peiretti

711 silver badge6 bronze badges

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