localstorage存储

来源：互联网发布：ubuntu 16.04 ibus 编辑：程序博客网时间：2024/06/05 03:23
define(function() {    var win = window,        doc = document,        decode = function(s) {            // 参考jquery cookie的实现: https://github.com/carhartl/jquery-cookie/blob/master/jquery.cookie.js            if (s.indexOf('"') === 0) {                s = s.slice(1, - 1).replace(/\\"/g, '"').replace(/\\\\/g, '\\');            }            try {                return decodeURIComponent(s);            } catch (e) {                return null;            }        },        encode = encodeURIComponent,        isSupportLocalStorage = (function() {            try {                var support = 'localStorage' in win && win['localStorage'] !== null,                    test = {                        k: 'test key',                        v: 'test value'                    };                if (support) {                    localStorage.setItem(test.k, test.v);                    support = test.v === localStorage.getItem(test.k);                }                return support;            } catch (e) {                return false;            }        }()),        stringify = function(v) {            if (!_.isString(v)) {                v = JSON.stringify(v);            }            return encode(v);        },        validateCookieName = function(name) {            if (!_.isString(name) || name === '') {                throw new TypeError('Cookie name must be a non-empty string!');            }        },        // TODO: 不支持localStorage时换用cookie存储        // 现在在某些浏览器下可能存在cookie数量的限制        // 之后可能的优化是使用subcookie的方式: https://developer.yahoo.com/yui/cookie/#subcookies        s = isSupportLocalStorage ? localStorage : {            setItem: function(k, v, days) {                validateCookieName(k);                // 默认cookie中的结果缓存7天                days = days || 7;                var expires = new Date();                expires.setDate(expires.getDate() + days);                v = _m.utils.evaluate(v);                if (_.isArray(v)) {                    v = v[0];                    expires = new Date(parseInt(v[1], 10));                }                k = stringify(k);                v = stringify(v);                // 高端浏览器中一般合并字符用+比用join('')更高效                // 参考: http://photo.weibo.com/2785671884/wbphotos/large/photo_id/3453950944633013?refer=weibofeedv5                doc.cookie = k + '=' + v + '; expires=' + expires.toGMTString();            },            getItem: function(k) {                validateCookieName(k);                k = stringify(k) + '=';                var v = null,                    cookie = doc.cookie,                    start = cookie.indexOf(k);                if (start > -1) {                    var end = cookie.indexOf(';', start);                    if (end === -1) {                        end = cookie.length;                    }                    v = decode(cookie.substring(start + k.length, end));                }                return v;            },            removeItem: function(k) {                this.setItem(k, '', - 1);            }        },        prefix = '_BM:';    return {        isSupportLocalStorage: isSupportLocalStorage,        set: function(k, v, expires) {            if (_.isNumber(expires)) {                expires = +new Date() + expires;            }            s.setItem(prefix + k, JSON.stringify({                value: v,                expires: expires            }));        },        get: function(k) {            var v = JSON.parse(s.getItem(prefix + k)),                expires;            if (!v) {                return;            }            expires = parseInt(v.expires, 10);            v = v.value;            if (expires) {                if (+new Date() < expires) {                    return v;                }                this.remove(k);            }            return v;        },        remove: function(k, v) {            if (v) {                try {                    this.set(k, _.difference(this.get(k), v));                } catch (e) {}            } else {                s.removeItem(prefix + k);            }        },        add: function(k, v, options) {            var h = this.get(k),                defaults = {                    type: 'set',                    limit: 10                },                opts = _.extend(defaults, options),                type = opts.type,                expires = opts.expires,                limit = opts.limit;            // TODO: 有潜在的bug, 比如之前存储的是array类型            if (!_.isArray(h)) {                h = _.isUndefined(h) && [] || [h];            }            if (type === 'set' && _.indexOf(h, v) !== -1) {                return;            }            if (_.isNumber(limit) && limit > 0) {                h = _.first(h, limit - 1);            }            h.unshift(v);            this.set(k, h, expires);        }    };});
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