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{"version":3,"file":"pick.cjs","names":["purry","out: Partial<Pick<T, Keys[number]>>"],"sources":["../src/pick.ts"],"sourcesContent":["import type { EmptyObject, IsNever, KeysOfUnion, Writable } from \"type-fest\";\nimport type { IsBounded } from \"./internal/types/IsBounded\";\nimport type { IsBoundedRecord } from \"./internal/types/IsBoundedRecord\";\nimport type { PartitionByUnion } from \"./internal/types/PartitionByUnion\";\nimport type { TupleParts } from \"./internal/types/TupleParts\";\nimport { purry } from \"./purry\";\n\ntype PickFromArray<T, Keys extends readonly KeysOfUnion<T>[]> =\n // Distribute unions for both object types and key arrays.\n T extends unknown\n ? Keys extends unknown\n ? // When T is a union (or when Keys is empty) the picked props might\n // not exist in some of its sub-types, e.g.,\n // `pick(... as { a: string } | { b: number }, ['a'])`,\n // if we simply let the regular \"constructive\" logic run, the\n // resulting type would be `{}` which doesn't behave like an empty\n // object! instead, we want to use a more explicit *empty* type.\n IsNever<Extract<Keys[number], keyof T>> extends true\n ? EmptyObject\n : // Remove `readonly` modifiers from picked props since we return a\n // new, mutable, object. We don't wrap the result with `Simplify` to\n // flatten it because `Writable` does the same thing implicitly.\n Writable<\n IsBoundedRecord<T> extends true\n ? PickBoundedFromArray<T, Keys>\n : PickUnbounded<T, Extract<Keys[number], keyof T>>\n >\n : never\n : never;\n\n/**\n * Bounded records have bounded keys and result in a bounded output. The only\n * question left is whether to add the prop as-is, or make it optional. This\n * can be determined by the part of the keys array the prop is defined in, and\n * the way that element is defined: if the array contains a singular literal\n * key in either the required prefix or the suffix, we know that prop should be\n * picked as-is, otherwise, the key might not be present in the keys array so it\n * can only be picked optionally.\n */\ntype PickBoundedFromArray<T, Keys extends readonly KeysOfUnion<T>[]> =\n // Literal keys in the prefix/suffix are guaranteed present.\n Pick<\n T,\n // When T is a union the keys need to be narrowed to just those that are\n // keys of the specific sub-type being built\n Extract<\n | PartitionByUnion<TupleParts<Keys>[\"required\"]>[\"singular\"]\n | PartitionByUnion<TupleParts<Keys>[\"suffix\"]>[\"singular\"],\n keyof T\n >\n > &\n // Union keys, optional elements, and rest elements are optional.\n Partial<\n Pick<\n T,\n // When T is a union the keys need to be narrowed to just those that are\n // keys of the specific sub-type being built.\n Extract<\n | PartitionByUnion<TupleParts<Keys>[\"required\"]>[\"union\"]\n // TODO: the optional part of the keys array will always be empty because its impossible to provide the pick function with a tuple with optional elements; this is because optional elements are always implicitly `undefined` too; which breaks the constraint that all keys are keys of T (`undefined` is not a key of anything). We can lift this restriction by supporting `undefined` in the runtime and relaxing the type constraint to allow it, but this relaxed constraint enables a niche feature (optional tuple elements) at the expense of better type-safety for the more common cases of fixed tuples and arrays. Anyway... if we ever change it, this part of the output type will ensure the output is still correct:\n | TupleParts<Keys>[\"optional\"][number]\n | TupleParts<Keys>[\"item\"]\n | PartitionByUnion<TupleParts<Keys>[\"suffix\"]>[\"union\"],\n keyof T\n >\n >\n >;\n\n/**\n * The built-in `Pick` is weird when it comes to picking bounded keys from\n * unbounded records. It reconstructs the output object regardless of the
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