JavaScript统计字符串字符出现次数的实现方法

JavaScript统计字符串字符出现次数实现

代码如下：

function numInstring(str) {
str = str.replace(/ /ig, "");
var strArr = str.split("");
var result = [], beforeLength, afterLength, reg;
for (var i = 0; i < strArr.length; i++) {
if (str.indexOf(strArr[i]) != -1) {
beforeLength = str.length;
reg = new RegExp(strArr[i], "ig");
str = str.replace(reg, "");
afterLength = str.length;
result.push(strArr[i] + ":" + (beforeLength - afterLength));
        }
    }
return result;
}
var result = numInstring("This section of the site is dedicated to the JavaScript language itself, the parts that are not specific to Web pages or other host");
console.log(result);
/*result:
["T:17", "h:7", "i:9", "s:10", "e:14", "c:5", "o:8", "n:3", "f:3", "d:3", "a:9", "J:1", "v:1", "r:5", "p:4", "l:2", "g:3", "u:1", ",:1", "W:1", "b:1"]
*/