prefer-is-for-primitives.md

uvu/prefer-is-for-primitives

Prefer is to equal for assertions against primitive literals.

Rationale

Methods is and equal act on primitive values almost identically, but give different messages when the test fails. This rule encourage use of is where available to get more informative messages on test failures. It also clarifies what types of value is expected in the test.

Examples

Examples of incorrect code for this rule:

import * as assert from "uvu/assert";
assert.equal(0, 0);

import { equal as uvuEqual } from "uvu/assert";
uvuEqual(0, 0);

Examples of correct code for this rule:

import * as assert from "uvu/assert";
assert.is(0, 0);
assert.equal([0], [0]);

Resources

• Rule source
• Test source