alexp95•2w ago

Function as a value?

I would like to know what is the best way to store a function as a value in a class because I am trying to track a constantly updating function

9 Replies

Leokuma•2w ago

Maybe myFunction.toString()

raunioroo•2w ago

Maybe im missing something from the question, but.. Functions in javascript are just values like string, number, or any other value. So, store it as is in a class member, just like you would store a string or any other type?

NDH•2w ago

If you need a class that will save constantly updating functions

class Funcy {
   funcs: Map<string, any[]> = new Map()

   // saves any change to a function
   // in a named array
   save(name: string, func: any) {
      if (this.funcs.has(name)) {
         const fList = this.funcs.get(name);
         if (fList) fList.push(func); // add function
      } else {
         this.funcs.set(name, [func]) // first one
      }
   }
   // retuen an array of all changes to 
   // a named function
   getAll(name) {
      return this.funcs.get(name)
   }
}

const funcy = new Funcy();
let myFunc1 = (e: string) => console.log(e);
funcy.save("myFunc", myFunc1)
let myFunc2 = (a: number) => console.log(a);
funcy.save("myFunc", myFunc2)

const myFuncs = funcy.getAll("myFunc");
console.log(myFuncs![1].toString())
myFuncs![0]("Yup!")

class Funcy {
   funcs: Map<string, any[]> = new Map()

   // saves any change to a function
   // in a named array
   save(name: string, func: any) {
      if (this.funcs.has(name)) {
         const fList = this.funcs.get(name);
         if (fList) fList.push(func); // add function
      } else {
         this.funcs.set(name, [func]) // first one
      }
   }
   // retuen an array of all changes to 
   // a named function
   getAll(name) {
      return this.funcs.get(name)
   }
}

const funcy = new Funcy();
let myFunc1 = (e: string) => console.log(e);
funcy.save("myFunc", myFunc1)
let myFunc2 = (a: number) => console.log(a);
funcy.save("myFunc", myFunc2)

const myFuncs = funcy.getAll("myFunc");
console.log(myFuncs![1].toString())
myFuncs![0]("Yup!")

©TriMoon™•2w ago

Maybe @alexp95 means getters? 🤔

class Rectangle {
  constructor(height, width) {
    this.height = height;
    this.width = width;
  }
  // Getter
  get area() {
    return this.calcArea();
  }
  // Method
  calcArea() {
    return this.height * this.width;
  }
  *getSides() {
    yield this.height;
    yield this.width;
    yield this.height;
    yield this.width;
  }
}

const square = new Rectangle(10, 10);

console.log(square.area); // 100
console.log([...square.getSides()]); // [10, 10, 10, 10]

class Rectangle {
  constructor(height, width) {
    this.height = height;
    this.width = width;
  }
  // Getter
  get area() {
    return this.calcArea();
  }
  // Method
  calcArea() {
    return this.height * this.width;
  }
  *getSides() {
    yield this.height;
    yield this.width;
    yield this.height;
    yield this.width;
  }
}

const square = new Rectangle(10, 10);

console.log(square.area); // 100
console.log([...square.getSides()]); // [10, 10, 10, 10]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes#methods

MDN Web Docs

Classes - JavaScript | MDN

Classes are a template for creating objects. They encapsulate data with code to work on that data. Classes in JS are built on prototypes but also have some syntax and semantics that are unique to classes.

©TriMoon™•2w ago

const obj = {
  log: ["a", "b", "c"],
  get latest() {
    return this.log[this.log.length - 1];
  },
};

console.log(obj.latest);
// Expected output: "c"

const obj = {
  log: ["a", "b", "c"],
  get latest() {
    return this.log[this.log.length - 1];
  },
};

console.log(obj.latest);
// Expected output: "c"

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/get

MDN Web Docs

get - JavaScript | MDN

The get syntax binds an object property to a function that will be called when that property is looked up. It can also be used in classes.

alexp95OP•2w ago

For that you do the same as any other code inside a string: You eval it...

alexp95OP•2w ago

Okay, thank you

PS: eval ing any code is not the solution to any coding problem, maybe you should rethink your actions... Most sites and browsers do not allow eval using CSP...

Function as a value?

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