JavaScript求指定范圍內的質數的實現代碼分享

//判斷是否為質數
function isPrime(number) {
	//0，1，負數肯定不是
 if(number < 2){
 return false;
 }
 var factor = Math.sqrt(number);
	//注意：這里是"<=factor"，而不是"<"
	//比如說25，factor是5，如果用"<"就會誤判
 for(var i=2;i<=factor;i++){
 if(number % i == 0){
 return false;
 }
 }
 return true;
}

//獲取范圍內的質數
function getPrimes(start, finish) {
	//確定上邊界
 var max = Math.max(start, finish);
	//確定下邊界
 var min = Math.min(start, finish);
 var result = [];
	//由小到大遍歷
 for(var i=min;i<=max;i++){
	//滿足質數條件，存入數組
 if(isPrime(i)){
 result.push(i);
 }
 }
 return result;
}

//[]
console.log(getPrimes(0, 0)); 
//[2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
console.log(getPrimes(0, 30));
//[2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
console.log(getPrimes(30, 0));