Class with an undefined function call

Question

Class with an undefined function call

Currently, I am working with angular2 and TypeScript where I have defined a class.

export class Example{

 //.../

   const self: all = this;
   functionToCall(){
      //.. Do somerthing
   }

   mainFunctionCall(){
      somepromise.then(x => self.functionToCall('url/'+ x.name ) )
   }
}

However, I keep encountering an error stating that functionToCall is undefined.

As I am fairly new to TypeScript/Angular, I wonder if there are any specific rules causing this issue. What is the correct way to call a method within a class from another method?

javascript angularjs typescript

Answer 1

Answer №1

No need to resort to a workaround in this situation, as lambda functions automatically capture the this reference from the surrounding scope. This can simplify your code like so:

const somepromise = Promise.resolve({name:"noone"});

class Example {

    functionToCall(x : string) {
        console.log(x);
    }

    mainFunctionCall() {
        somepromise.then(x => this.functionToCall('url/'+ x.name ) )
    }
}

(new Example()).mainFunctionCall();

Edit Updated code snippet includes all necessary details and is runnable in the typescript playground.

Answer 2

No need to resort to a workaround in this situation, as lambda functions automatically capture the this reference from the surrounding scope. This can simplify your code like so:

const somepromise = Promise.resolve({name:"noone"});

class Example {

    functionToCall(x : string) {
        console.log(x);
    }

    mainFunctionCall() {
        somepromise.then(x => this.functionToCall('url/'+ x.name ) )
    }
}

(new Example()).mainFunctionCall();

Edit Updated code snippet includes all necessary details and is runnable in the typescript playground.

Class with an undefined function call

Answer №1

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