collectype / factory/strings/stringMembership / stringMembershipFactory
stringMembershipFactory<
T,C>(ctx,oper): <K>(field,target) =>C
Defined in: factory/strings/stringMembership.ts:40
Creates a predicate filter for string membership using PredicType.string.membership.
T
The item type in the collection.
C extends Wherable<T, C>
The Wherable context type (must extend Wherable<T, C>).
C
The context (usually a collection) supporting the where method.
StringMembershipOper
The string membership operation to perform (see PredicType.string.membership).
Returns a function that takes a field (of type string on T) and a target array, and applies the string membership predicate to filter the context.
<
K>(field,target):C
K extends string | number | symbol
K
string[]
C
// Example: Composing a string membership filter as a property, homogeneous model
import { BaseFunctions } from 'collectype';
import { stringMembershipFactory } from 'collectype';
type Person = { name: string; city: string };
class PersonFunctions extends BaseFunctions<Person> {
stringIn = stringMembershipFactory<Person, this>(this, 'in');
}
// Usage:
const people: Person[] = [
{ name: 'Alice', city: 'Paris' },
{ name: 'Bob', city: 'Lyon' },
{ name: 'Eve', city: 'Paris' }
];
const fn = new PersonFunctions(people);
const filtered = fn.stringIn('city', ['Paris', 'Lyon']);
// filtered contains the items where 'city' is in ['Paris', 'Lyon']
PredicType.string.membership for string membership on string fields.