在 keydown 时从数组返回非重复随机项

Question

 var myArray = [ ["a", "a1", "a2", "a3"] //["b", "b1", "b2", "b3"], //["c", "c1", "c2", "c3"] ]; function getRandom(arr) { if (arr.length === 0) { return arr } var a = Math.floor(Math.random() * arr.length); var b = arr.splice(a, 1); console.log(b[0]) return b[0]; } function compare(entry, string) { for (var x in entry) { array1 = entry[x][0].split(' '); if (array1.includes(string)) { items = entry[x].slice(1); return getRandom(items) } } } $("#input").keydown(function(e) { keyword = $(this).val(); if (e.which === 13) { $(this).val(""); text = keyword.toLowerCase(); result = '<div>' + compare(myArray, text) + '</div>' $('#results').append(result); } });

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <input id="input" type="text" placeholder="Search..." autocomplete="off" /> <div id="results" class="reset">

getRandom function should get random item, return and remove that item, then restart the process when the original array is equal to zero but it's not working...

To test, enter a into input box. The result I need should be a1, a2, and a3 one at a time in random order for the first three attempts then restart the process. Thanks for your help!

Answer 1

The problem is that you pass items to getRandom, which is the function that alters its argument ... but items is created using the slice method, which creates a brand new array (in fact, one way to make an exact copy of an array that we can change without affecting the original is is arr.slice() ). So the changes made by getRandom will not alter myArray .