Question 413022 in Javascript Question posted in
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Javascript – How to declare a true #private field with Symbol?

I try to declare private Symbol property in ES6+ class, below’s approach are all wrong.

class MyClass {
  #[Symbol.for('my-symbol-prop1')] = 'my-symbol-prop1';  // SyntaxError
  [#Symbol.for('my-symbol-prop1')] = 'my-symbol-prop1';  // SyntaxError
}

My question: Is there any way to declare a true private Symbol property, just using hash notation like #myPrivateSymbolfield, don’t using WeakMap or enclosure approach

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2

Answers


  1. 0

    Currently in JavaScript, there isn’t a direct way to create private Symbol properties using the private field syntax (#). The private fields feature and Symbol properties serve different purposes. Having said that, you can easily do a workaround for the same i.e. use a static private field to store the symbol. Something like below:

    class MyClass {
  [Symbol.for('my-symbol-prop')] = 'symbol';
  
  // Private Symbol wokraround using private field
  static #privateSymbol = Symbol('privateSymbol Desc');
  
  constructor() {
    /* The Symbol itself can be accessed via the getter
    but the property using this Symbol is still private */

    this[MyClass.#privateSymbol] = 'private symbol value';
  }
  
  get privateSymbolValue() {
    return this[MyClass.#privateSymbol];
  }
}
// Usage
const myClass1 = new MyClass();
const myClass2 = new MyClass();
console.log(myClass1.privateSymbolValue);
console.log(myClass2.privateSymbolValue);
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  2. 0

    This is not possible. Symbol-keyed properties are just regular object properties (just with symbols instead of string names), not private fields. If you want a field with a private name, do not use symbols.

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