monocle-ts-esm/es6/Index/Array.js

A porting of scala monocle library to TypeScript

/**
 * @since 1.2.0
 */
import { Index, Optional } from '..';
import { lookup, updateAt } from 'fp-ts-esm/Array';
import { isNone } from 'fp-ts-esm/Option';
/**
 * @category constructor
 * @since 1.2.0
 */
export function indexArray() {
    return new Index((i) => new Optional((as) => lookup(i, as), (a) => (as) => {
        const oas = updateAt(i, a)(as);
        if (isNone(oas)) {
            return as;
        }
        else {
            return oas.value;
        }
    }));
}