A lazy/optimized expression detection method
I recently put together a chrome extension for a customer who wanted to detect predefined expressions in webpages. Given the size of the targetted web pages, he was concerned about performance and did not want the web site / browser to be slowed down by the extra processing involved. I designed a triple blade razor contentScript based on two web APIs which can help with the job: Blade1: to deal with any web page including the dynamic ones, I configured a mutationObserver to detect the newly created DOM elements. By the way, I'm only interested by the elements which contain text nodes (i.e. nodeType===Node.TEXT_NODE).. Blade2/ to spend CPU time on useful things, I configured an intersectionObserver to which I passed those elements. This observer detects the nodes becoming visible and feeds those to the third blade. Blade3/ finally, a simple job scheduler scans its pipeline every 5 ms and communicates with the background script which holds the content processing engine (in