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pickBy

pickBy() function​

Returns a partial copy of an object which contains only the keys that satisfy the supplied predicate.

Signature: 
declare function pickBy<T extends object, F extends EntryPredicate<T>>(f: F, obj: T): Partial<T>;

declare function pickBy<T extends object, F extends EntryPredicate<T>>(f: F): (obj: T) => Partial<T>;

declare function pickBy<T extends object, F extends AsyncEntryPredicate<T>>(f: F, obj: T): Promise<Partial<T>>;

declare function pickBy<T extends object, F extends AsyncEntryPredicate<T>>(f: F): (obj: T) => Promise<Partial<T>>;

declare function pickBy<T extends object, F extends ConditionalAsyncEntryPredicate<T>>(f: F, obj: T): Partial<T> | Promise<Partial<T>>;

declare function pickBy<T extends object, F extends ConditionalAsyncEntryPredicate<T>>(f: F): (obj: T) => Partial<T> | Promise<Partial<T>>;

Example​

const obj = { a: 1, b: "2", c: true };
pickBy(([key, value]) => key === "a" || value === true, obj); // { a: 1, c: true }

// asynchronous predicate
await pickBy(async ([key, value]) => key === "a" || value === true, obj); // { a: 1, c: true }

// Using with the `pipe` function
pipe(
  obj,
  pickBy(([key, value]) => key === "a" || value === true)
);

await pipe(
  obj,
  pickBy(async ([key, value]) => key === "a" || value === true)
);

see pipe, pick,

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