Calling a method from another method in the same class

Question

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?

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Answer 1

class MyClass {

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

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

}

var myClass = new MyClass();

myClass.runMyTest();

use arrow function to bind this within a function. it works fine even on typescript

Answer 2

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

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

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

Answer 3

class MyClass {

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

    runMyTest() {
      this.myTest();
    }

}

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

Answer 4

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();
    }
}

Answer 5

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();

Answer 6

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