The example in this article describes the implementation of a JavaScript array object to add a method that returns random elements. Share it with everyone for your reference. The details are as follows:
Core features:
Random probability, random order, random bubbling
This method comes from personal handwriting JavaScript practice, only involves the JavaScript 1.5 (ECMAscript 3 international standard) language itself, and is common in all JS engine implementations~
Add random method to Array object:
(function () { function Random_SN(iArray) { return Math.floor(Math.random() * iArray.length); } function Probability_Random(iArray) { var Random_Int; if (iArray.Random_SN === undefined) iArray.Random_SN = -1; do Random_Int = Random_SN(iArray); while ( Random_Int == iArray.Random_SN ) iArray.Random_SN = Random_Int; return iArray[Random_Int]; } function Sequence_Random(iArray) { return iArray.splice(Random_SN(iArray), 1)[0]; } Array.prototype.random = function (Mode, Pop) { if (! Mode) return Probability_Random(this); if (! Pop) { if (! (this.Random_Queue && this.Random_Queue.length)) this.Random_Queue = [].concat(this); return Sequence_Random(this.Random_Queue); } return Sequence_Random(this); }; })();
Usage example:
// 【概率随机】 // // 元素的返回 完全随机,出现几率不定,有限次调用不保证能返回所有元素 var iElement = iArray.random(); // 【顺序随机】 // // 元素的返回 有周期性,在每个周期内,元素都出现一次,但顺序不定 var iElement = iArray.random(true); // 【随机冒泡】 // // 每次调用都从原数组中随机取出一个元素返回(原数组 就地改变) var iElement = iArray.random(true, true);
I hope this article will be helpful to everyone’s JavaScript programming design.