prefer-equality-assertion

📝 Prefer an equality assertion over a truthiness assertion on a comparison.

💼 This rule is enabled in the following configs: ✅ recommended, ☑️ unopinionated.

🔧 This rule is automatically fixable by the --fix CLI option.

Asserting a comparison through a truthiness assertion (assert(actual === expected) or assert.ok(actual === expected)) throws away the diagnostic. On failure, Node only reports that the expression evaluated to a falsy value:

AssertionError: The expression evaluated to a falsy value:

  assert.ok(actual === expected)

The dedicated equality assertion reports both values and a diff instead, which is far easier to debug.

This rule reports assert()/assert.ok() calls whose argument is an equality comparison and autofixes to the assertion that preserves the operator's semantics. Relational comparisons (<, >, <=, >=) are not reported because node:assert has no equivalent assertion.

Operator	Replacement
===	strictEqual
!==	notStrictEqual
==	equal
!=	notEqual

Loose ==/!= comparisons are not reported when using a strict assert API because equal/notEqual would behave strictly there and change the assertion semantics.

The fix is skipped (the problem is still reported) when the comparison is wrapped in extra parentheses or contains a comment, since the rewrite could not safely preserve it.

Examples

import assert from 'node:assert';

// ❌
assert.ok(actual === expected);
assert(actual !== expected);
assert.ok(actual === expected, 'should match');

// ✅
assert.strictEqual(actual, expected);
assert.notStrictEqual(actual, expected);
assert.strictEqual(actual, expected, 'should match');