Summary

Before, the sources parameter had a strict type, so unless a user intentionally hacked around the type system, null or undefined values were never passed.
Later, while making the type compatible with Lodash, it became possible to pass nil (null or undefined) values.
When this happened, compat/defaults would throw an error, while Lodash’s defaults would simply ignore those values without a problem.

This change fixes that issue by making compat/defaults handle nil values the same way as Lodash — safely skipping them without errors.

Before Change

The following code would throw an error when a null or undefined source parameter is provided:

import { defaults as esDefaults } from "es-toolkit/compat";

function main() {
  esDefaults({ a: 1 }, null);
}

main();

Note: In Lodash’s defaults, passing null or undefined as a source does not cause an error — it simply ignores those values.
The current behavior in es-toolkit is inconsistent with that.

After Change

The defaults function has been updated to safely ignore null or undefined sources.
If a nil (null/undefined) source is passed, it will simply be skipped without throwing an error.

import { defaults as esDefaults } from "es-toolkit/compat";

function main() {
  esDefaults({ a: 1 }, null); // returns { a: 1 }
}

main();

Testing

Coverage