add typescript definitions, update readme

.gitignore

@@ -1,2 +1,3 @@
 index.cjs.js
 node_modules/
+index.d.ts

README.md

@@ -19,7 +19,9 @@ npm i --save fzy.js
 `score(needle, haystack)`
 
 ``` javascript
-var fzy = require('fzy.js')
+var fzy = require('fzy.js') // CJS
+
+// import * as fzy from "fzy.js" // ESM
 
 fzy.score("amuser", "app/models/user.rb")     // 5.595
 fzy.score("amuser", "app/models/customer.rb") // 3.655
@@ -41,8 +43,9 @@ See the full example below for a way to do this check.
 # Full Example
 
 ``` javascript
-var { sortBy, escapeRegExp } = require("lodash");
-var fzy = require("fzy.js");
+var fzy = require('fzy.js') // CJS
+
+// import * as fzy from "fzy.js" // ESM
 
 // List of candidate strings
 // Often generated by something like require("glob")("**/*")
@@ -56,10 +59,10 @@ var list = [
 var query = "amuser";
 
 // fzy.js includes `hasMatch` which can be used for filtering
-list = list.filter((s) => fzy.hasMatch(s));
+list = list.filter((s) => fzy.hasMatch(query, s));
 
 // Sort by fzy's scoring, descending (higher scores are better matches)
-list = sortBy(list, (s) => -fzy.score(query, s));
+list = list.sort((a,b) => fzy.score(query, b) - fzy.score(query, a));
 
 // Select only the first 10 results
 list.slice(0, 10);
@@ -84,5 +87,5 @@ list.forEach((s) => {
 //
 // app/models/customer.rb
 // a   m       us   er
-
 ```
+

index.js

@@ -1,3 +1,4 @@
+// @ts-check
 var SCORE_MIN = -Infinity;
 var SCORE_MAX = Infinity;
 
@@ -10,14 +11,23 @@ var SCORE_MATCH_WORD = 0.8
 var SCORE_MATCH_CAPITAL = 0.7
 var SCORE_MATCH_DOT = 0.6
 
+/**
+ * @param {string} s
+ */
 function islower(s) {
 	return s.toLowerCase() === s;
 }
 
+/**
+ * @param {string} s
+ */
 function isupper(s) {
 	return s.toUpperCase() === s;
 }
 
+/**
+ * @param {string} haystack
+ */
 function precompute_bonus(haystack) {
 	/* Which positions are beginning of words */
 	var m = haystack.length;
@@ -45,14 +55,20 @@ function precompute_bonus(haystack) {
 	return match_bonus;
 }
 
+/**
+ * @param {string} needle
+ * @param {string} haystack
+ * @param {number[][]} D
+ * @param {number[][]} M
+ */
 function compute(needle, haystack, D, M) {
 	var n = needle.length;
 	var m = haystack.length;
 
 	var lower_needle = needle.toLowerCase();
 	var lower_haystack = haystack.toLowerCase();
 
-	var match_bonus = precompute_bonus(haystack, match_bonus);
+	var match_bonus = precompute_bonus(haystack);
 
 	/*
 	 * D[][] Stores the best score for this position ending with a match.
@@ -88,6 +104,11 @@ function compute(needle, haystack, D, M) {
 	}
 }
 
+/**
+ * @param {string} needle
+ * @param {string} haystack
+ * @returns {number}
+ */
 function score(needle, haystack) {
 	var n = needle.length;
 	var m = haystack.length;
@@ -120,6 +141,11 @@ function score(needle, haystack) {
 	return M[n - 1][m - 1];
 }
 
+/**
+ * @param {string} needle
+ * @param {string} haystack
+ * @returns {number[]}
+ */
 function positions(needle, haystack) {
 	var n = needle.length;
 	var m = haystack.length;
@@ -144,7 +170,10 @@ function positions(needle, haystack) {
 
 	compute(needle, haystack, D, M)
 
-	/* backtrack to find the positions of optimal matching */
+	/**
+	 * backtrack to find the positions of optimal matching
+	 * @type {number | boolean}
+	 */
 	var match_required = false;
 
 	for (var i = n - 1, j = m - 1; i >= 0; i--) {
@@ -175,6 +204,11 @@ function positions(needle, haystack) {
 	return positions;
 }
 
+/**
+ * @param {string} needle
+ * @param {string} haystack
+ * @returns {boolean}
+ */
 function hasMatch(needle, haystack) {
   needle = needle.toLowerCase()
   haystack = haystack.toLowerCase()