riot-query/src/index.js

'use strict';

const dedupe = require("dedupe");
const queryParser = require("./query");
const flatten = require("./flatten-query");
const tagQueries = require("./tag-queries");

function ensureArray(item) {
	if (Array.isArray(item)) {
		return item;
	} else if (item == null) {
		return [];
	} else {
		return [item];
	}
}

function recurseTags(tag) {
	let allTags = [tag];

	Object.keys(tag.tags).forEach((tagType) => {
		ensureArray(tag.tags[tagType]).forEach((subTag) => {
			allTags = allTags.concat(recurseTags(subTag));
		});
	});

	return allTags;
}

function createQuery(query) {
	let {riotQuery, domQuery} = queryParser.parse(query);
	let flattenedQueries = flatten(riotQuery);
	tagQueries(flattenedQueries);

	return function traverse(tag) {
		let results = [];

		flattenedQueries.forEach((subQuery) => {
			let lastFound = [tag];

			subQuery.forEach((segment) => {
				let nextLastFound = [];

				lastFound.forEach((subTag) => {
					//console.log("subtag", subQuery, segment, subTag);
					let found;

					if (segment.type === "identifier") {
						found = ensureArray(subTag.tags[segment.value]);
					} else if (segment.type === "wildcard") {
						found = recurseTags(subTag);
					}

					if (found.length > 0) {
						nextLastFound = nextLastFound.concat(found)
					}
				});

				lastFound = nextLastFound;
			});

			results = results.concat(lastFound);
		});

		return dedupe(results, result => result._riot_id);
	}
}

let queryCache = {};

module.exports = function(tag, query) {
	if (queryCache[query] == null) {
		queryCache[query] = createQuery(query);
	}

	// TODO: DOM traversal

	return queryCache[query](tag);
}