Function defineIfNotExists

defineIfNotExists<T extends object>(
    prototype: T,
    name: string,
    fn: Function,
): void
Defines a non-enumerable, non-writable, non-configurable property on a prototype if it does not already exist, or if the existing property is writable or configurable.
- Intended for instance prototype methods (e.g., Array.prototype, String.prototype).
- Does not overwrite non-configurable and non-writable properties.
- Ensures immutability and hides the property from enumeration.
Type Parameters
- T extends object
  The prototype object type (e.g., Array.prototype).
Parameters
- prototype: T
  The prototype on which to define the method.
- name: string
  The name of the method to define.
- fn: Function
  The function to assign as the method.
Returns void
Example
```
defineIfNotExists(Array.prototype, 'last', function() {
  return this[this.length - 1];
});
```
Remarks
Use this function to safely add prototype methods without overwriting stable or built-in ones.
- Defined in src/utils/core.utils.ts:22