js 实现类似 Java 中的 StringBuilder

前端页面中对字符串的拼接操作是还是比较多的, 为此自己写了一个类似Java中StringBuilder的类, 以减轻字符串拼接工作, 有待改进.

;(function(window, undefined) {    if (typeof window.StringBuilder === 'function') {        return window.StringBuilder;    }    function filterString(input) {        var type = typeof input,            result = '';        if (input === null || type === 'undefined') {            return result;        }        // for string, number, boolean, also NaN        result += input;        return result;    }    StringBuilder = function(initStr) {        this.array = [filterString(initStr)];    };    StringBuilder.prototype = {        constructor: StringBuilder,        append: function(input) {            this.array.push(filterString(input));            return this;        },        isEmpty: function() {            return this.array.length === 0;        },        clear: function() {            this.array.length = 0;            return this;        },        // delete: function(start, end) {        //  // if only start given, then delete one char which index is start        //  if (typeof end === 'undefined') {        //      this.array.splice(start, 1);        //  } else {        //      this.array.splice(start, end - start);        //  }        //  return this;        // },        reverse: function() {            var thisArr = this.array,                len = thisArr.length,                i = -1;            if (len === 1) {                thisArr[0] = thisArr[0].split('').reverse().join('');            } else {                while (++i < len) {                    thisArr[i] = thisArr[i].split('').reverse().join('');                }                thisArr.reverse();            }            return this;        },        toString: function() {            return this.array.join('');        },        valueOf: function() {            return this.toString();        }    };    window.StringBuilder = StringBuilder;})(window);