Type Alias ApplyDefaultOptions<Options, Defaults, SpecifiedOptions>

ApplyDefaultOptions: If<
    IsAny<SpecifiedOptions>,
    Defaults,
    If<
        IsNever<SpecifiedOptions>,
        Defaults,
        Simplify<
            Merge<
                Defaults,
                {
                    [Key in keyof SpecifiedOptions as Key extends OptionalKeysOf<
                        Options,
                    >
                        ? undefined extends SpecifiedOptions[Key] ? never : Key
                        : Key]: SpecifiedOptions[Key]
                },
            > & Required<Options>,
        >,
    >,
>

type PathsOptions = {maxRecursionDepth?: number; leavesOnly?: boolean};
type DefaultPathsOptions = {maxRecursionDepth: 10; leavesOnly: false};
type SpecifiedOptions = {leavesOnly: true};

type Result = ApplyDefaultOptions<PathsOptions, DefaultPathsOptions, SpecifiedOptions>;
//=> {maxRecursionDepth: 10; leavesOnly: true}
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// Complains if default values are not provided for optional options

type PathsOptions = {maxRecursionDepth?: number; leavesOnly?: boolean};
type DefaultPathsOptions = {maxRecursionDepth: 10};
type SpecifiedOptions = {};

type Result = ApplyDefaultOptions<PathsOptions, DefaultPathsOptions, SpecifiedOptions>;
//                                              ~~~~~~~~~~~~~~~~~~~
// Property 'leavesOnly' is missing in type 'DefaultPathsOptions' but required in type '{ maxRecursionDepth: number; leavesOnly: boolean; }'.
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// Complains if an option's default type does not conform to the expected type

type PathsOptions = {maxRecursionDepth?: number; leavesOnly?: boolean};
type DefaultPathsOptions = {maxRecursionDepth: 10; leavesOnly: 'no'};
type SpecifiedOptions = {};

type Result = ApplyDefaultOptions<PathsOptions, DefaultPathsOptions, SpecifiedOptions>;
//                                              ~~~~~~~~~~~~~~~~~~~
// Types of property 'leavesOnly' are incompatible. Type 'string' is not assignable to type 'boolean'.
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// Complains if an option's specified type does not conform to the expected type

type PathsOptions = {maxRecursionDepth?: number; leavesOnly?: boolean};
type DefaultPathsOptions = {maxRecursionDepth: 10; leavesOnly: false};
type SpecifiedOptions = {leavesOnly: 'yes'};

type Result = ApplyDefaultOptions<PathsOptions, DefaultPathsOptions, SpecifiedOptions>;
//                                                                   ~~~~~~~~~~~~~~~~
// Types of property 'leavesOnly' are incompatible. Type 'string' is not assignable to type 'boolean'.
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