Skip to main content

Null safety

Null handling is explicit per operation:

  • defaults replaces only null and undefined.
  • Built-in normalizers return null for nullish, empty, or invalid values.
  • mapEach turns a null or undefined list into [].
  • rename, normalize, defaults, and merge expect an object; they do not turn a null root value into an object.

Valid falsy values are preserved by defaults:

defaults({count: 10, enabled: true})({count: 0, enabled: false});
// {count: 0, enabled: false}

Normalization is intentionally different because it converts inconsistent external values:

normalize({count: 'number', active: 'boolean'})(
  {count: 'not-a-number', active: undefined},
);
// {count: null, active: null}