How to call your method on a string?

• 0
  
  How it works? Why are we calling methods on the string? Where are they generally defined?
  It looks like extensions like in c # and I tried to write my own:
  
  Unfortunately, it doesn't work.

  JavaScript Anonymous, Nov 4, 2019

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2 Answers
• 0
  The primitive is wrapped in an object of the corresponding type and uses the methods of its prototype. In fact:
  
  (new String ('hello')). toUpperCase ();

  Emmett Copeland

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• 0
  An instance of the String object is created with a toUpperCase () method, the methods are defined inside String.prototype (try typing in the console). To add your own method, extend the prototype of the desired object:

  String.prototype.myLength = function( arg ) {
  
      // ваш код
  
  };

  Anonymous

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