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    Type Alias IsStringLiteral<S>

    IsStringLiteral: IfNotAnyOrNever<
        S,
        {
            ifAny: false;
            ifNever: false;
            ifNot: _IsStringLiteral<CollapseLiterals<UnwrapBrand<S>>>;
        },
    >

    Returns a boolean for whether the given type is a string literal type.

    The implementation of this type is inspired by the trick mentioned in this StackOverflow answer.

    Type Parameters

    • S
    import type {IsStringLiteral} from 'type-fest';

    type A = IsStringLiteral<'foo'>;
    //=> true

    type B = IsStringLiteral<string>;
    //=> false

    // String types with infinite set of possible values return `false`
    type C = IsStringLiteral<`on${string}`>;
    //=> false

    type D = IsStringLiteral<Uppercase<string>>;
    //=> false

    type E = IsStringLiteral<'foo' | 'bar' | 'baz'>;
    //=> true

    type F = IsStringLiteral<'sm' | 'md' | 'lg' | `${number}px`>;
    //=> boolean

    import type {IsStringLiteral} from 'type-fest';

    type StringLength<S extends string, Counter extends never[] = []> =
    	IsStringLiteral<S> extends true
    		? S extends `${string}${infer Tail}`
    			? StringLength<Tail, [...Counter, never]>
    			: Counter['length']
    		: number; // return `number` for non-literal string types

    type L1 = StringLength<'foobar'>;
    //=> 6

    type L2 = StringLength<Lowercase<string>>;
    //=> number

    type L3 = StringLength<`${number}`>;
    //=> number

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