Pull Up Constructor Body

Removes smells

Symptom

Multiple subclass constructors initialize the same parent fields with the same logic; the agent verifying constructors must check every subclass for consistency.

Goal

Shared initialization lives in the parent's constructor and runs via super; subclass constructors hold only their specific setup, and the agent reads one canonical init for parent-state setup.

Before the refactoring

class Manager  extends Employee { constructor(n, s) { this.name = n; this.salary = s; } }
class Engineer extends Employee { constructor(n, s) { this.name = n; this.salary = s; } }

After the refactoring

class Employee {
  constructor(name, salary) { this.name = name; this.salary = salary; }
}
class Manager  extends Employee {}
class Engineer extends Employee {}

Example source: Illustrative example written for this site, not a quotation from any source.

Pressure

Bug fixes in init logic must land in every subclass; the agent must update each consistently or risk silent drift.

Tradeoff

Subclasses that need different parent-state setup pay the cost of overriding the pulled-up init or passing flags through super; the agent reading those overrides loads both the parent's shared init and the subclass's override to predict what runs.

Relief

New subclasses inherit the parent's init without re-declaring it; edits to the shared setup land in one constructor and the agent loads one body to verify the change instead of N near-identical subclass constructors.

Trap

Pulling up init logic only some subclasses need forces the others to override with awkward opt-outs the agent must reason about.