Rule proposal: `no-useless-recursion`

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Description

function foo(bar) {
  if (bar.baz) {
    return foo(bar.baz);
  }

  return bar;
}

function foo(bar) {
  while (bar.baz) {
    bar = bar.baz:
  }

  return bar;
}

function foo(bar) {
  for (; bar.baz; bar = bar.baz) {}

  return bar;
}

function foo(bar) {
  if (Array.isArray(bar)) {
    return bar.map(baz => foo(bar));
  }

  return bar;
}

Contributor guide

Research direction

The issue proposes a new ESLint rule to detect 'useless recursion' where a function tail calls itself with the same or transformed argument without a base case. The main challenge is defining 'simple' recursion precisely. Review comments (e.g., #1078) suggest discussing the scope, such as whether to flag only tail recursive calls or any self call without a stopping condition. Check existing ESLint rules like no useless return or no useless catch for pattern. Consult the eslint plugin unicorn documentation on rule creation (in lib/rules/) and test conventions. Engage with maintainers to clarify the definition before implementation.

Tech stack

javascript

Domain

developer experiencetooling

Issue type

Feature

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

3-5 days

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

Needs maintainer response

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

Mostly clear

Prerequisites

AST knowledgeESLint plugin developmentJavaScript

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

45