How do I replace a buggy method in a class when the method calls super.method()?

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Summary

This incident revolves around a buggy inherited method in a JavaScript class hierarchy where the child class must call super.method(), but the framework’s implementation is faulty. The engineer wants a temporary workaround without modifying framework source code and without losing access to the correct ancestor implementation.

Root Cause

The core issue stems from JavaScript’s super binding rules, specifically:

  • super relies on the method’s [[HomeObject]] internal slot.
  • Monkeypatched functions do not have a [[HomeObject]], so super.method() becomes impossible.
  • JavaScript does not support super.super.method() or skipping levels in the prototype chain.
  • The framework’s buggy method sits in the middle of the inheritance chain, making normal overrides insufficient.

Why This Happens in Real Systems

Real-world frameworks often:

  • Implement deep inheritance chains where one bad override breaks all subclasses.
  • Use non‑configurable or non‑replaceable methods.
  • Assume consumers will not need to bypass intermediate classes.
  • Provide no hooks or extension points for patching behavior.

Real-World Impact

This leads to:

  • Blocked releases because a framework bug prevents correct behavior.
  • Risky monkeypatches that break language semantics.
  • Duplicated logic when engineers re‑implement parent behavior manually.
  • Fragile workarounds that may break on framework updates.

Example or Code (if necessary and relevant)

A safe workaround is to directly call the grandparent prototype method, bypassing the buggy override:

class SubClass extends BaseClass {
  method() {
    // buggy implementation
    super.method();
  }
}

class SubSubClass extends SubClass {
  method() {
    // call BaseClass.prototype.method directly
    BaseClass.prototype.method.call(this);

    // add fixed behavior
    // ...
  }
}

This avoids super.super.method() (which does not exist) while still invoking the correct ancestor method.

How Senior Engineers Fix It

Experienced engineers typically:

  • Call the desired ancestor method explicitly, bypassing the buggy one.
  • Isolate the workaround in a single subclass to minimize blast radius.
  • Document the workaround so future maintainers understand the deviation.
  • Guard the fix with feature detection or version checks.
  • Remove the workaround once the upstream fix ships.

Why Juniors Miss It

Less experienced engineers often struggle because:

  • They assume super behaves like other languages and supports multi-level access.
  • They are unaware of [[HomeObject]] and why monkeypatching breaks super.
  • They try to override the buggy method without realizing the prototype chain can be accessed manually.
  • They expect the framework to provide extension points and don’t consider direct prototype calls as a valid escape hatch.

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