JavaScript Cookie Utils

cookie-utils.js

// Example #1: Simple usage
document.cookie = "name=oeschger";
document.cookie = "favorite_food=tripe";
function alertCookie() {
    console.log(document.cookie);
}

// Example #2: Get a sample cookie named test2
document.cookie = "test1=Hello";
document.cookie = "test2=World";
var cookieValue = document.cookie.replace(/(?:(?:^|.*;\s*)test2\s*\=\s*([^;]*).*$)|^.*$/, "$1");


// Example #3: Do something only once
// In order to use the following code, please replace all occurrences of the word doSomethingOnlyOnce (the name of the cookie) with a custom name.
function doOnce() {
    if (document.cookie.replace(/(?:(?:^|.*;\s*)doSomethingOnlyOnce\s*\=\s*([^;]*).*$)|^.*$/, "$1") !== "true") {
        alert("Do something here!");
        document.cookie = "doSomethingOnlyOnce=true; expires=Fri, 31 Dec 9999 23:59:59 GMT";
    }
}

// Example #4: Reset the previous cookie
function resetOnce() {
    document.cookie = "doSomethingOnlyOnce=; expires=Thu, 01 Jan 1970 00:00:00 GMT";
}

// Example #5: Check a cookie existence
// ES5
if (document.cookie.split(';').filter(function(item) {
    return item.trim().indexOf('reader=') == 0
}).length) {
    console.log('The cookie "reader" exists (ES5)')
}
// ES2016
if (document.cookie.split(';').filter((item) => item.trim().startsWith('reader=')).length) {
    console.log('The cookie "reader" exists (ES6)')
}

// Example #6: Check that a cookie has a specific value
// ES5
if (document.cookie.split(';').filter(function(item) {
    return item.indexOf('reader=1') >= 0
}).length) {
    console.log('The cookie "reader" has "1" for value')
}
// ES2016
if (document.cookie.split(';').filter((item) => item.includes('reader=1')).length) {
    console.log('The cookie "reader" has "1" for value')
}

function getCookieByRegEx(regex) {
    console.log('getCookieForRegEx:', regex, '\n', 'cookie:', document.cookie);
}

getCookieByRegEx(/foo/);