collectype / factory/strings/stringState / stringStateFactory
stringStateFactory<
T,C>(ctx,oper): <K>(field) =>C
Defined in: factory/strings/stringState.ts:40
Creates a predicate filter for string state using PredicType.string.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.
StringStateOper
The string state operation to perform (see PredicType.string.state).
Returns a function that takes a field (of type string on T) and applies the string state predicate to filter the context.
<
K>(field):C
K extends string | number | symbol
K
C
// Example: Composing a string state filter as a property, homogeneous model
import { BaseFunctions } from 'collectype';
import { stringStateFactory } from 'collectype';
type Person = { name: string; city: string };
class PersonFunctions extends BaseFunctions<Person> {
stringIsEmpty = stringStateFactory<Person, this>(this, 'isEmpty');
}
// Usage:
const people: Person[] = [
{ name: 'Alice', city: 'Paris' },
{ name: 'Bob', city: '' },
{ name: 'Eve', city: 'Rome' }
];
const fn = new PersonFunctions(people);
const filtered = fn.stringIsEmpty('city');
// filtered contains the items where 'city' is an empty string
PredicType.string.state for string state checks on string fields.