FuzzySet Class — svelte Architecture

Source Code

packages/svelte/src/compiler/phases/1-parse/utils/fuzzymatch.js lines 124–279

class FuzzySet {
	/** @type {Record<string, string>} */
	exact_set = {};

	/** @type {Record<string, [number, number][]>} */
	match_dict = {};

	/** @type {Record<string, number[]>} */
	items = {};

	/** @param {string[]} arr */
	constructor(arr) {
		// initialisation
		for (let i = GRAM_SIZE_LOWER; i < GRAM_SIZE_UPPER + 1; ++i) {
			this.items[i] = [];
		}

		// add all the items to the set
		for (let i = 0; i < arr.length; ++i) {
			this.add(arr[i]);
		}
	}

	/** @param {string} value */
	add(value) {
		const normalized_value = value.toLowerCase();
		if (normalized_value in this.exact_set) {
			return false;
		}

		let i = GRAM_SIZE_LOWER;
		for (i; i < GRAM_SIZE_UPPER + 1; ++i) {
			this._add(value, i);
		}
	}

	/**
	 * @param {string} value
	 * @param {number} gram_size
	 */
	_add(value, gram_size) {
		const normalized_value = value.toLowerCase();
		const items = this.items[gram_size] || [];
		const index = items.length;

		items.push(0);
		const gram_counts = gram_counter(normalized_value, gram_size);
		let sum_of_square_gram_counts = 0;
		let gram;
		let gram_count;

		for (gram in gram_counts) {
			gram_count = gram_counts[gram];
			sum_of_square_gram_counts += Math.pow(gram_count, 2);
			if (gram in this.match_dict) {
				this.match_dict[gram].push([index, gram_count]);
			} else {
				this.match_dict[gram] = [[index, gram_count]];
			}
		}
		const vector_normal = Math.sqrt(sum_of_square_gram_counts);
		// @ts-ignore no idea what this code is doing
		items[index] = [vector_normal, normalized_value];
		this.items[gram_size] = items;
		this.exact_set[normalized_value] = value;
	}

	/** @param {string} value */
	get(value) {
		const normalized_value = value.toLowerCase();
		const result = this.exact_set[normalized_value];

		if (result) {
			return /** @type {MatchTuple[]} */ ([[1, result]]);
		}

		// start with high gram size and if there are no results, go to lower gram sizes
		for (let gram_size = GRAM_SIZE_UPPER; gram_size >= GRAM_SIZE_LOWER; --gram_size) {
			const results = this.__get(value, gram_size);
			if (results.length > 0) return results;
		}