1function deleteCookie(name) {
2  document.cookie = name + '=; expires=Thu, 01 Jan 1970 00:00:01 GMT;';
3}

1function setCookie(name,value,days) {
2    var expires = "";
3    if (days) {
4        var date = new Date();
5        date.setTime(date.getTime() + (days*24*60*60*1000));
6        expires = "; expires=" + date.toUTCString();
7    }
8    document.cookie = name + "=" + (value || "")  + expires + "; path=/";
9}
10function getCookie(name) {
11    var nameEQ = name + "=";
12    var ca = document.cookie.split(';');
13    for(var i=0;i < ca.length;i++) {
14        var c = ca[i];
15        while (c.charAt(0)==' ') c = c.substring(1,c.length);
16        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
17    }
18    return null;
19}
20
21setCookie("user_email","bobthegreat@gmail.com",30); //set "user_email" cookie, expires in 30 days
22var userEmail=getCookie("user_email");//"bobthegreat@gmail.com"

1function setCookie(name,value,days) {
2    var expires = "";
3    if (days) {
4        var date = new Date();
5        date.setTime(date.getTime() + (days*24*60*60*1000));
6        expires = "; expires=" + date.toUTCString();
7    }
8    document.cookie = name + "=" + (value || "")  + expires + "; path=/";
9}
10function getCookie(name) {
11    var nameEQ = name + "=";
12    var ca = document.cookie.split(';');
13    for(var i=0;i < ca.length;i++) {
14        var c = ca[i];
15        while (c.charAt(0)==' ') c = c.substring(1,c.length);
16        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
17    }
18    return null;
19}
20function eraseCookie(name) {   
21    document.cookie = name +'=; Path=/; Expires=Thu, 01 Jan 1970 00:00:01 GMT;';
22}
23

1const setCookie = (options) => {
2  const {
3    name,
4    value = '',
5    path = '/',
6    duration = 3600,
7  } = options;
8  
9  const durationMs = duration * 1000;
10  const expires =
11    new Date(Date.now() + durationMs);
12
13  document.cookie = 
14    `${name}=${escape(value)}; expires=${expires.toUTCString()}; path=${path}`;
15}
16
17const getCookie = (name, cast = String) => {
18  if (document.cookie.length == 0)
19    return;
20
21  const match = document
22    .cookie
23    .match(`${name}=(?<value>[\\w]*);?`);
24
25  if (!match)
26    return;
27
28  const value =
29    match?.groups?.value ?? '';
30
31  return cast(unescape(value));
32}
33
34const cookieExists = (name) => {
35  return getCookie(name) !== undefined;
36}
37
38const deleteCookie = (name) => {
39  setCookie({
40    name: name,
41    value: undefined,
42    duration: -1,
43  });
44}
45
46
47// Example string
48setCookie({ 
49  name: 'username',
50  value: 'dude',
51});
52
53const username = 
54  getCookie('username');
55
56
57// Example number
58setCookie({
59  name: 'count',
60  value: 100,
61  duration: 300, // 300s, 5 minutes
62});
63
64const count =
65  getCookie('count', parseInt);
66
67deleteCookie('count');

1
2 function setCookie(cname, cvalue, exdays) {
3
4   const d = new Date();
5  d.setTime(d.getTime() + (exdays*24*60*60*1000));
6  let expires = "expires="+ d.toUTCString();
7  document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
8}
9 

1For storing array inside cookie : 
2-----------------------------------
3setter : var json_str = JSON.stringify(arr); cookie.set('mycookie', json_str);
4getter : cookie.get('mycookie'); var arr = JSON.parse(json_str);
5----------------------------------------------------------------------------
6Function common for all type of variable : 
7==========================================
8let cookie = {
9            set: function(name, value) {
10                document.cookie = name+"="+value;
11            },
12            get: function(name) {
13                let nameEQ = name + "=";
14                let ca = document.cookie.split(';');
15                for( let i = 0; i < ca.length; i++ ) {
16                    let c = ca[i];
17                    while (c.charAt(0)==' ') c = c.substring(1,c.length);
18                    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
19                }
20                return null;
21            }
22        }