Type alias IsNull<T, $O>

🎭 predicate

Validate if T is null.

Example

type R = IsNull<null> // true

type R = IsNull<never> // false
type R = IsNull<unknown> // false
type R = IsNull<string | boolean> // false

type R = IsNull<string | null> // boolean
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🔢 customize

Filter to ensure T is null, otherwise returns never.

Example

type R = IsNull<null, { selection: 'filter' }> // null

type R = IsNull<never, { selection: 'filter' }> // never
type R = IsNull<unknown, { selection: 'filter' }> // never
type R = IsNull<string | boolean, { selection: 'filter' }> // never

type R = IsNull<string | null> // null
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🔢 customize:

Disable distribution of union types.

type R = IsNull<null | 1> // boolean
type R = IsNull<null | 1, { distributive: false }> // false
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🔢 customize

Use unique branch identifiers to allow precise processing of the result.

Example

type R = IsNull<null, $SelectionBranch> // $Then
type R = IsNull<string, $SelectionBranch> // $Else
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