[js高手之路] 跟GhostWu一起封装一个字符串工具库-扩展字符串位置方法(4)

本文，我们接着之前的框架继续扩展，这次扩展了一共有5个与字符串位置相关的方法

between( left, right )

返回两个字符串之间的内容， 如果第二个参数没有传递，返回的是找到的第一个参数 之后 到 字符串结尾的所有字符串

如果第二个参数传递了，但是从left这个位置查找不到，就返回空字符串

例子：

G( 'ghost wu tell you how to learn js' ).between( 'tell', 'learn' ).s   

返回的是tell和learn之间的字符串, 结果为:you how to

G( 'ghost wu tell you how to learn js' ).between( 'tell' ).s

返回的是tell后面所有的字符串，结果为:you how to learn js

G( 'ghost wu tell you how to learn js' ).between( 'tell', 'wu' ).s

返回空字符串

 

chompLeft( prefix )

例子:返回以prefix开头 到 字符串结尾的所有字符串

G( 'ghost wu tell you how to learn js' ).chompLeft( 'tell' ).s; //ghost wu tell you how to learn js

G( 'ghost wu tell you how to learn js' ).chompLeft( 'ghost' ).s; //wu tell you how to learn js

 

startWith( prefix ): 判断是否以prefix这个字符串开始

endWith( prefix ): 判断是否以prefixe这个字符串结尾

G( 'ghost wu tell you how to learn js---ghost wu' ).startWith('wu');//false

G( 'ghost wu!asbc# ghost wu' ).endWith('wu');//true

 

chompRight( prefix )

例子:返回从字符串开始到以prefix结尾之间的字符串

G( 'ghost wu tell you how to learn js---ghost wu' ).chompRight('wu').s;//ghost wu tell you how to learn js---ghost

 

; (function (window, undefined) {
    function init(obj, s) {
        if (s !== null && s !== undefined) {
            if (typeof s === 'string') {
                obj.s = s;
            } else {
                obj.s = s.toString();
            }
        } else {
            obj.s = s;
        }
    }

    function G(s) {
        init(this, s);
    }

    function GhostWu(s) {
        return new G(s);
    }

    var sProto = String.prototype;
    G.prototype = {
        constructor: G,
        capitalize: function () {
            return new this.constructor(this.s.slice(0, 1).toUpperCase() + this.s.substring(1).toLowerCase());
        },
        trimLeft: function () {
            var s;
            if (sProto.trimLeft === 'undefined')
                s = this.s.trimLeft();
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                s = this.s.replace(/^s+/g, '');
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        trimRight: function () {
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        trim: function () {
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            return new this.constructor(s);
        },
        camelize: function () {
            var s = this.trim().s.replace(/(-|_|s)+(.)?/g, function (s0, s1, s2) {
                return (s2 ? s2.toUpperCase() : '');
            });
            return new this.constructor(s);
        },
        dasherize: function () {
            var s = this.trim().s.replace(/[_s]+/g, '-').replace(/([A-Z])/g, '-$1').replace(/-+/g, '-').toLowerCase();
            return new this.constructor(s);
        },
        between: function (left, right) {
            var s = this.s;
            var startPos = s.indexOf(left);
            var endPos = s.indexOf(right, startPos + left.length);
            if (endPos == -1 && right != null)
                return new this.constructor('')
            else if (endPos == -1 && right == null)
                return new this.constructor(s.substring(startPos + left.length))
            else
                return new this.constructor(s.slice(startPos + left.length, endPos));
        },
        chompLeft: function (prefix) {
            var s = this.s;
            if (s.indexOf(prefix) === 0) {
                s = s.slice(prefix.length);
                return new this.constructor(s);
            } else {
                return this;
            }
        },
        startWith: function () {
            var prefixes = [].slice.call(arguments, 0);
            if (this.s.indexOf(prefixes[0], 0) === 0) return true;
            return false;
        },
        endWith: function () {
            var prefixes = [].slice.call(arguments, 0),
                pos = 0;
            while (pos !== -1) {
                if (this.s.indexOf(prefixes[0], pos) === (this.s.length - prefixes[0].length)) return true;
                pos = this.s.indexOf(prefixes[0], pos + prefixes[0].length);
            }
            return false;
        },
        chompRight: function (suffix) {
            if (this.endWith(suffix)) {
                var s = this.s;
                s = s.slice(0, s.length - suffix.length);
                return new this.constructor(s);
            } else {
                return this;
            }
        }
    };

    window.G = GhostWu;
})(window, undefined);