collectype / factory/objects/objectState / objectStateFactory
objectStateFactory<
T,C>(ctx,oper): <K>(field) =>C
Defined in: factory/objects/objectState.ts:40
Creates a predicate filter for object state using PredicType.object.state.
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.
ObjectStateOper
The object state operation (e.g., ‘is_plain’, ‘is_empty’, etc.).
Returns a function that takes a field (of type object on T) and applies the object state predicate to filter the context.
<
K>(field):C
K extends string | number | symbol
K
C
// Example: Composing an object state filter as a property, homogeneous model
import { BaseFunctions } from 'collectype';
import { objectStateFactory } from 'collectype';
type Person = { name: string; meta: { country?: string } };
class PersonFunctions extends BaseFunctions<Person> {
objectIsEmpty = objectStateFactory<Person, this>(this, 'is_empty');
}
// Usage:
const people: Person[] = [
{ name: 'Alice', meta: {} },
{ name: 'Bob', meta: { country: 'US' } }
];
const fn = new PersonFunctions(people);
const filtered = fn.objectIsEmpty('meta');
// filtered contains the items where 'meta' is empty