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June 9, 2020 21:00
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Polyfills localStorage and sessionStorage when cookies are disabled.
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const hasLocalStorage = (function(){ | |
try { | |
localStorage.setItem('mod', 'mod'); | |
localStorage.removeItem('mod'); | |
return true; | |
} catch(e) { | |
return false; | |
} | |
})() | |
if (!hasLocalStorage) { | |
(function () { | |
var Storage = function (type) { | |
function createCookie(name, value, days) { | |
var date, expires; | |
if (days) { | |
date = new Date(); | |
date.setTime(date.getTime()+(days*24*60*60*1000)); | |
expires = "; expires="+date.toGMTString(); | |
} else { | |
expires = ""; | |
} | |
document.cookie = name+"="+value+expires+"; path=/"; | |
} | |
function readCookie(name) { | |
var nameEQ = name + "=", | |
ca = document.cookie.split(';'), | |
i, c; | |
for (i=0; i < ca.length; i++) { | |
c = ca[i]; | |
while (c.charAt(0)==' ') { | |
c = c.substring(1,c.length); | |
} | |
if (c.indexOf(nameEQ) == 0) { | |
return c.substring(nameEQ.length,c.length); | |
} | |
} | |
return null; | |
} | |
function setData(data) { | |
// Convert data into JSON and encode to accommodate for special characters. | |
data = encodeURIComponent(JSON.stringify(data)); | |
// Create cookie. | |
if (type == 'session') { | |
createCookie(getSessionName(), data, 365); | |
} else { | |
createCookie('localStorage', data, 365); | |
} | |
} | |
function clearData() { | |
if (type == 'session') { | |
createCookie(getSessionName(), '', 365); | |
} else { | |
createCookie('localStorage', '', 365); | |
} | |
} | |
function getData() { | |
// Get cookie data. | |
var data = type == 'session' ? readCookie(getSessionName()) : readCookie('localStorage'); | |
// If we have some data decode, parse and return it. | |
return data ? JSON.parse(decodeURIComponent(data)) : {}; | |
} | |
function getSessionName() { | |
// If there is no name for this window, set one. | |
// To ensure it's unquie use the current timestamp. | |
if(!window.name) { | |
window.name = new Date().getTime(); | |
} | |
return 'sessionStorage' + window.name; | |
} | |
// Initialise if there's already data. | |
var data = getData(); | |
return { | |
length: 0, | |
clear: function () { | |
data = {}; | |
this.length = 0; | |
clearData(); | |
}, | |
getItem: function (key) { | |
return data[key] === undefined ? null : data[key]; | |
}, | |
key: function (i) { | |
// not perfect, but works | |
var ctr = 0; | |
for (var k in data) { | |
if (ctr == i) return k; | |
else ctr++; | |
} | |
return null; | |
}, | |
removeItem: function (key) { | |
delete data[key]; | |
this.length--; | |
setData(data); | |
}, | |
setItem: function (key, value) { | |
data[key] = value+''; // forces the value to a string | |
this.length++; | |
setData(data); | |
} | |
}; | |
}; | |
// Replace window.localStorage and window.sessionStorage with out custom | |
// implementation. | |
var localStorage = new Storage('local'); | |
var sessionStorage = new Storage('session'); | |
Object.defineProperty(window, "localStorage", { value: localStorage }) | |
Object.defineProperty(window, "sessionStorage", { value: sessionStorage }) | |
})(); | |
} |
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FYI this does not cover all cases - I'm seeing
TypeError: Attempting to change access mechanism for an unconfigurable property.
at line 120 for Safari 9.x in our monitoring systems.