1 Array.prototype.shuffle = function () {
2 for (let i = this.length - 1; i > 0; i--) {
3 const j = Math.floor(Math.random() * (i + 1)); // random index 0..i
4 [this[i], this[j]] = [this[j], this[i]]; // swap elements
11 // find viable rows from json data
12 let rows = Object.values(json);
13 if (this.preset.cat !== undefined) {
14 let cats = {}; // category lookup
17 if (!cats[cat]) cats[cat] = [];
22 let children = cats[this.preset.cat];
23 for (let loop = 0; children.length && loop < 20; loop++) {
24 rows.push(...children);
25 children = children.map(cat => cats[cat]).filter(is => is).flat();
27 rows = rows.map(row => json[row]).filter(row => row[2]);
29 if (this.preset.level !== undefined) {
30 rows = rows.filter(row => row[1] <= this.preset.level);
35 let subcats = rows.map(row => row[3]); // direct parents
36 for (let loop = 0; subcats.length && loop < 20; loop++) {
37 subcats.forEach(cat => cats.add(cat));
38 subcats = subcats.map(row => json[row] && json[row][3]).filter(val => val); // recurse grandparents
40 rows = rows.filter(row => !cats.has(row[2])); // remove referenced categories
42 return rows.shuffle();
47 fetch(dataurl).then(res => res.json()).then(json => {
48 this.words = this.dataselect(json)
53 constructor(dataurl) {