Type alias IsNotUndefined<T, $O>

🎭 predicate

Validate if T is not undefined.

Example

type R = IsNotUndefined<undefined> // false

type R = IsNotUndefined<never> // true
type R = IsNotUndefined<unknown> // true
type R = IsNotUndefined<string | boolean> // true
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🔢 customize

Filter to ensure T is not undefined, otherwise returns never.

Example

type R = IsNotUndefined<undefined, { selection: 'filter' }> // never

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

Disable distribution of union types.

Example

type R = IsNotUndefined<undefined | 1> // boolean
type R = IsNotUndefined<undefined | 1, { distributive: false }> // true
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🔢 customize

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

Example

type R = IsNotUndefined<string, $SelectionBranch> // $Then
type R = IsNotUndefined<undefined, $SelectionBranch> // $Else
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