The function cannot be found within the specified file

Question

The function cannot be found within the specified file

Snippet.ts

export class Snippet {

public async processData(data): Promise<any> {

//processing logic

    }
}

Snippet.spec.ts

 //correctly imported Snippet class

    describe('testing', async () =>{
       it('ProcessData test call', async ()=>{
            let result = await Snippet.processData(data:any) //this line shows error as processData does not exist on type 'typeof SnippetService'
    });
});

Although the Snippet class has been imported correctly, there seems to be an issue with calling the function within the Snippet.spec.ts.

javascript typescript import es6-class angular2-testing

Answer 1

Answer №1

This mistake is quite simple actually. You are trying to call the method on the class function directly, instead of on an object of the class's instance type.

If you want to call the method without creating an instance, like in your sample code, you should declare it as static:

export class Example {
   static async initService(Id) {}
}

However, if you intend for it to be an instance method, you must create an instance first to call the method:

export class Example {
   async initService(Id) {}
}

 describe('testing', async () => {
    it('InitService test call', async () => {
      const x = await new Example().initService(1);
    });
 });

Lastly, the phrase error message is because the type of the class function itself is declared as typeof ClassFunction, while its instances are simply referred to as `ClassFunction`.

Answer 2

This mistake is quite simple actually. You are trying to call the method on the class function directly, instead of on an object of the class's instance type.

If you want to call the method without creating an instance, like in your sample code, you should declare it as static:

export class Example {
   static async initService(Id) {}
}

However, if you intend for it to be an instance method, you must create an instance first to call the method:

export class Example {
   async initService(Id) {}
}

 describe('testing', async () => {
    it('InitService test call', async () => {
      const x = await new Example().initService(1);
    });
 });

Lastly, the phrase error message is because the type of the class function itself is declared as typeof ClassFunction, while its instances are simply referred to as `ClassFunction`.

The function cannot be found within the specified file

Answer №1

Similar questions

creating images using express.js

Persist form input data using ajax without any back-end server logic involved

Retrieve values of properties from an array

Generate a fresh DOM element when a particular height threshold is achieved, utilizing a portion of the previous DOM element's content

I encountered an import error while attempting to set up Kivy on my system

Is it possible to send notifications via email prior to reaching a particular deadline?

Using AngularJS to dynamically swap out {{post.title}} with a different HTML file

The transition to CDK version 2 resulted in a failure of our test cases

In D3 Hierarchy Typescript, every parent-child duo is assigned the same color

Oops! The program encountered an issue where it couldn't access the "Point" property because it was undefined. This occurred while working with openlayers 3 and jsts on

Issue with Transmitting Selected Value from Select Menu to the Server

Creating a Vertical Navbar Dropdown in Bootstrap 3.0 Without Appending to the Last List Item Only

How can you make an element appear when clicking and then disappear with a second click?

Is it necessary to utilize process.env in node.js?

Expanding angularjs date filter to support additional date formats

Using Vue to display a Div inside a TD element of a table does not result in a reactive behavior

When attempting to use the .split method, an error is thrown stating that addEventListener is not

What are the differences between performing a search in MongoDB (database component) and Node.js (server-side)?

Trigger the function of a Jquery plugin once AngularJS has finished rendering

Why does Prettier choose to omit trailing commas?