no-extend-native.md

Pattern: Extension of native object prototype

Issue: -

Description

Extending built-in native objects by adding properties to their prototypes can lead to unexpected behavior, naming conflicts, and compatibility issues across different JavaScript environments. Create utility functions or separate objects instead.

Examples

Example of incorrect code:

Object.prototype.extraMethod = function() {};
Array.prototype.customFilter = function() {};
String.prototype.trim = function() {};

Object.defineProperty(Array.prototype, 'sum', {
  value: function() {}
});

Example of correct code:

class CustomArray extends Array {
  customFilter() {}
}

const arrayUtils = {
  sum: function(array) {}
};

function trim(str) {
  return str.trim();
}

class Enhanced {
  extraMethod() {}
}