In my naive junior days I've reimplemented some excel sheets in php/mysql/javascript (plain js, without any frameworks) but it essentially worked and behaved ex

In my naive junior days I've reimplemented some excel sheets in php/mysql/javascript (plain js, without any frameworks) but it essentially worked and behaved exactly like those sheets. It took about 10min to recalculate all of the data (essentially summarizing all sheets from 600 car dealerships through 4 sheet levels plus some light analytics, should take max 5s with proper programming) and used 8gb of memory (biggest server for a webdev) but it worked. So if someone joked that it was excel underneath - it was half of excel implemented in php because we could not get actual excel to work properly with php COM.