Bookmarklet that adds "+before:date" to courrent url = if you search on gmail it will add "before:YYYY-MM-DD" to current search! So you can do yesterbox, by each search query you use ! (be careful with just "label:X" queries as they form URL differently)
/* Current View!!! (Adds "before:YYYY-MM-DD" to current URL ! -> gmail search view) */
javascript:(function(){ var d=new Date(); var curr=location.href; location.replace(curr+'+before:'+d.getFullYear()+'-'+(d.getMonth()+1)+'-'+d.getDate()); })(); /* http://stackoverflow.com/a/29808878 */
Bookmarklet opening new tab/new window with before:
set to current date
javascript:(function(){ var d=new Date(); window.open('https://mail.google.com/mail/u/0/#search/is:inbox+before:'+d.getFullYear()+'-'+(d.getMonth()+1)+'-'+d.getDate()); })();
Easily adopted with "is:important" or "is:unimportant" :
javascript:(function(){ var d=new Date(); window.open('https://mail.google.com/mail/u/0/#search/is:inbox+is:important+before:'+d.getFullYear()+'-'+(d.getMonth()+1)+'-'+d.getDate()); })();
javascript:(function(){ var d=new Date(); window.open('https://mail.google.com/mail/u/0/#search/is:inbox+is:unimportant+before:'+d.getFullYear()+'-'+(d.getMonth()+1)+'-'+d.getDate()); })();
And here are versions opening in current tab/window :
javascript:(function(){ var d=new Date(); location.replace('https://mail.google.com/mail/u/0/#search/is:inbox+is:unimportant+before:'+d.getFullYear()+'-'+(d.getMonth()+1)+'-'+d.getDate()); })(); /* http://stackoverflow.com/a/29808878 */
javascript:(function(){ var d=new Date(); location.replace('https://mail.google.com/mail/u/0/#search/is%3Ainbox+is%3Aimportant+before:'+d.getFullYear()+'-'+(d.getMonth()+1)+'-'+d.getDate()); })(); /* http://stackoverflow.com/a/29808878 */
and also with "starred" criteria
javascript:(function(){ var d=new Date(); location.replace('https://mail.google.com/mail/u/0/#search/is:inbox+is:unimportant+-is:starred+before:'+d.getFullYear()+'-'+(d.getMonth()+1)+'-'+d.getDate()); })(); /* http://stackoverflow.com/a/29808878 */
javascript:(function(){ var d=new Date(); location.replace('https://mail.google.com/mail/u/0/#search/is%3Ainbox+(is%3Aimportant+OR+is%3Astarred)+before:'+d.getFullYear()+'-'+(d.getMonth()+1)+'-'+d.getDate()); })(); /* http://stackoverflow.com/a/29808878 */
References: https://www.mattcutts.com/blog/javascript-bookmarklet-basics/