Difference between private keyword and private fields in TypeScript. The Complete TypeScript Developer Course 2023 [Videos].

TypeScript 3.8 supports the private keyword to declare its members private. And the private fields in TypeScript are the ones newly proposed for JavaScript. These fields are preceded by #.

Private keyword: The private keyword in TypeScript is used to mark a member private which makes it inaccessible outside the declared class. The fields are preceded by the private keyword to mark them private.

• Syntax:

  private variableName

• Example:

  class letters {      private a;        constructor(alphabet){          this.a = alphabet;     }        getA(){         return this.a;     } }  const l = new letters("gfg");  console.log(l.getA());

• Output:

  gfg

Private fields: Private fields in TypeScript are the ones that have been newly added to JavaScript, the members to be declared private are preceded by a #. Private members cannot be accessed outside their class.

• Syntax:

  #variableName

• Example:

  class letters {     #a;       constructor(alphabet){         this.#a = alphabet;     }       getA(){         return this.#a;     } } const l = new letters("gfg"); console.log(l.getA());

  Output:

• gfg

Hence, to implement the private keyword in runtime when compiling TypeScript to ESNext JavaScript one must consider using the private syntax # defined for JavaScript.

Difference between private keyword and private fields: