DefinitelyTyped/types/flat/flat-tests.ts

import { flatten, unflatten } from "flat";

namespace TestFlatten {
	type Target = {
		a: {
			b: number;
		},
		c: boolean[][];
	};

	let target: Target;

	type Result = {
		'a.b': number;
		'c.0.0': boolean;
	};

	let result: Result;

	result = flatten<Target, Result>(target);
	result = flatten<Target, Result>(target, {});
	result = flatten<Target, Result>(target, {
	    delimiter: '_',
    });
    result = flatten<Target, Result>(target, {
        maxDepth: 3,
    });
    result = flatten<Target, Result>(target, {
        safe: true,
    });
    result = flatten<Target, Result>(target, {
        transformKey: (key: string) => key,
    });
}

namespace TestUnflatten {
	type Target = {
		'a.b': number;
		'c.0.0': boolean;
	};

	let target: Target;

	type Result = {
		a: {
			b: number;
		},
		c: boolean[][];
	};

	let result: Result;

	result = unflatten<Target, Result>(target);
    result = unflatten<Target, Result>(target, {});
    result = unflatten<Target, Result>(target, {
        delimiter: '_',
    });
    result = unflatten<Target, Result>(target, {
        object: true,
    });
    result = unflatten<Target, Result>(target, {
        overwrite: true,
    });
    result = unflatten<Target, Result>(target, {
        transformKey: (key: string) => key,
    });
}