import * as O from "./optic.ts";
import * as Op from "./option.ts";

const key = (key: string) => <A>() =>
  O.prism<Record<string, A>, A>(
    rec => Op.fromNullable(rec[key]),
    a => ({ [key]: a }),
    mod => s => Object.hasOwn(s, key) ? ({ ...s, [key]: mod(s[key]) }) : s,
  );

const atFoo = key("foo")<number>();

const result1 = atFoo.view({ bar: 1 }); // None
const result2 = atFoo.view({ foo: 2 }); // Some(2)
const result3 = atFoo.review(5); // { foo: 5 }
const result4 = atFoo.modify(n => n + 1)({ bar: 1 }); // { bar: 1 }
const result5 = atFoo.modify(n => n + 1)({ foo: 1 }); // { foo: 2 }
const result6 = atFoo.modify(n => n + 1)({ foo: 1, bar: 2 });
// { foo: 2, bar: 2 }