collectype

collectype v0.11.0


collectype / factory/arrays/arrayMembership / arrayMembershipFactory

Function: arrayMembershipFactory()

arrayMembershipFactory<T, C>(ctx, oper): <K>(field, target) => C

Defined in: factory/arrays/arrayMembership.ts:40

Creates a predicate filter for array membership using PredicType.array.membership.

Type Parameters

T

T

The item type in the collection.

C

C extends Wherable<T, C>

The Wherable context type (must extend Wherable<T, C>).

Parameters

ctx

C

The context (usually a collection) supporting the where method.

oper

ArrayMembershipOper

The array membership operation (e.g., ‘in’, ‘notIn’, etc.).

Returns

Returns a function that takes a field (of type array on T) and a target value, and applies the array membership predicate to filter the context.

<K>(field, target): C

Type Parameters

K

K extends string | number | symbol

Parameters

field

K

target

unknown

Returns

C

Example

// Example: Composing an array membership filter as a property, homogeneous model
import { BaseFunctions } from 'collectype';
import { arrayMembershipFactory } from 'collectype';

type Person = { name: string; groups: string[] };

class PersonFunctions extends BaseFunctions<Person> {
  arrayIn = arrayMembershipFactory<Person, this>(this, 'in');
}

// Usage:
const people: Person[] = [
  { name: 'Alice', groups: ['admin', 'user'] },
  { name: 'Bob', groups: ['user'] }
];
const fn = new PersonFunctions(people);
const filtered = fn.arrayIn('groups', 'admin');
// filtered contains the items where 'groups' contains 'admin'

Remarks