"use strict";

const isIterable = require("is-iterable");
const forEach = require("../for-each");

module.exports = function treeMap(tree, mapper, options = {}) {
	let key = options.key ?? "children";
	let recurseAfterMap = options.recurseAfterMap ?? false;

	let results = [];

	function step(subtree) {
		let mapped = mapper(subtree);

		results.push(mapped);

		let nextChildren = (recurseAfterMap)
			? mapped[key]
			: subtree[key];

		if (isIterable(nextChildren)) {
			forEach(nextChildren, step);
		} else if (nextChildren != null && typeof nextChildren === "object") {
			step(nextChildren);
		}
	}

	if (isIterable(tree)) {
		forEach(tree, step);
	} else {
		step(tree);
	}

	return results;
};