assertStrict

Prefer strict assertion mode from Node.js for better error messages and behavior.

✅ This rule is included in the node logical preset.

In strict assertion mode, non-strict methods like deepEqual() behave like their strict counterparts (deepStrictEqual()). Strict mode provides better error messages with diffs and more reliable equality checks, reducing the risk of false positives in tests.

Examples

❌ Incorrect

import assert from "assert";

import assert from "node:assert";

import { deepEqual } from "node:assert";

✅ Correct

import assert from "assert/strict";

import assert from "node:assert/strict";

import { strict as assert } from "node:assert";

import { strict } from "node:assert";

Options

This rule is not configurable.

When Not To Use It

If you specifically need the non-strict behavior of assertion methods (for example, when testing legacy code that relies on coercive equality), you might choose not to enable this rule.

Further Reading

• Node.js: Strict assertion mode
• Node.js: Assert module

Equivalents in Other Linters

• Biome: useNodeAssertStrict