CODEWITHSUNDEEP
javascriptecmascript-6
steve-o
steve-o

Reputation: 1403

Calling a method from another method in the same class

Why am I getting the error: "Uncaught TypeError: self.myTest is not a function"? How do I call a method from within another method in a javascript class?

class MyClass {

    myTest() {
      console.log('it works');
    }

    runMyTest() {
      self.myTest();
    }

}

var myClass = new MyClass();
myClass.runMyTest();

Upvotes: 64

Views: 124694

Answers (8)

Rahul Somaraj
Rahul Somaraj

Reputation: 277

class MyClass {

 myTest() {
  console.log('it works');
 }

 runMyTest = ()=>{
  this.myTest();  
 }

 runMyTest2 = function(){
  this.myTest(); 
 }
}

var myClass = new MyClass();
myClass.runMyTest();
myClass.runMyTest2();

use arrow function to bind this to the global object. To represnt objects properties we have to use function

 let user = {
    name :"Something"
 }

 user.value = ()=>{
   console.log(this)
 }

 user.value2 = function(){
   console.log(this)
 }

   user.value(); ///returns this for windows
   user.value2(); ///returns object user

Upvotes: 5

Nafsin Vk
Nafsin Vk

Reputation: 647

The below is an ideal way to call a function in the same class. if it is NodeJS.

NodeJS

var self;
class SampleClass {
  constructor(tableName) {
    self = this;
  }
  secondFunction(param) {
    console.log(`called secondFunction with ${param}`)
  }
  firstFunction(param) {
    console.log(`called firstFunction with ${param}`)
    self.secondFunction(param);
  }
  async callableFunction(param) {
    self.firstFunction(param)
  }
};
module.exports = SampleClass

ES-6

class SampleClass {
  constructor(tableName) {
    //empty constructor or fill with what you need on init
  }
  secondFunction(param) {
    console.log(`called secondFunction with ${param}`)
  }
  firstFunction(param) {
    console.log(`called firstFunction with ${param}`)
    this.secondFunction(param);
  }
  async callableFunction(param) {
    this.firstFunction(param)
  }
};

var SampleClassObject = new SampleClass()
SampleClassObject.callableFunction('Argument as string!')

Upvotes: -1

Miguel Alcantar
Miguel Alcantar

Reputation: 9

class MyClass(){
    constructor(){
         this.init();
    }

    init(){
         const $this = this;
         this.doSomethigElse();
    }

    doSomethingElse(){
         console.log("It worked!");
    }
}

Upvotes: -1

Salah Eddib
Salah Eddib

Reputation: 1

class MyClass {

    myTest() {
      console.log('it works');
    }

    runMyTest() {
      this.myTest();
    }

}

var myClass = new MyClass();
myClass.runMyTest();

Upvotes: -1

Toby Mellor
Toby Mellor

Reputation: 8215

You need to use the this keyword instead of self.

runMyTest() {
    this.myTest();
}

A side note

If you are nesting standard functions notation then this is not lexically bound (will be undefined). To get around this, use Arrow Functions (preferred), .bind, or locally define this outside of the function.

class Test {
  constructor() {
    this.number = 3;
  }

  test() {
    function getFirstThis() {
       return this;
    }

    const getSecondThis = () => {
       return this;
    };

    const getThirdThis = getFirstThis.bind(this);
    
    const $this = this;
    function getFourthThis() {
      return $this;
    }

    // undefined
    console.log(getFirstThis());
    
    // All return "this" context, containing the number property
    console.log(this); 
    console.log(getSecondThis());
    console.log(getThirdThis());
    console.log(getFourthThis());
  }
}

new Test().test();

Upvotes: 67

edi
edi

Reputation: 937

You need to use this not self like

runMyTest() {
  this.myTest();
}

However a lot of implementations like to keep the reference and are doing the following:

var self = this;

That might be the reason you were thinking of self as self reference. For further reading I'd suggest this SO - post

Upvotes: 12

user7396942
user7396942

Reputation:

Other solution is save the value of variable context $this inside other for example in this

and for use is this.anyFunction();

class MyClass {
    myTest() {
      console.log('it works');
    }

    runMyTest() {
      let this=$this;
      this.myTest();
    }
}

Upvotes: -2

M Melnikov
M Melnikov

Reputation: 83

class MyClass {

    myTest() {
      console.log('it works');
    }

    runMyTest() {
      this.myTest();
    }

}

var myClass = new MyClass();
myClass.runMyTest();

Upvotes: 3

Related Questions