« Lazarus: Form Recovery » is a Firefox add-on that saves the text of the forms so it can be restored later (very handy, for example if you have typed a long mail/message/Wikipedia contribution and something bad happens, like a crash or a computer shutdown).

Unfortunately, I realized that it causes a small delay (something like 1.5s) when submitting a form. It is perceptible in the case of an Ajax form (or even an « offline » form where nothing is sent but data is processed locally in Javascript; in this case the result should be instant). I spend some times searching around, it was crazy! No problem with a simple « onClick » but only with « onSubmit ». Was it the debug version of React? No! Or the fact that I used the Javascript compilation of React JSX? No! There was nothing special in the Performance analyser. Then I realized that Chromium was fast. And Firefox dev edition was fast. Then I began the Firefox add-on hunt…

That’s strange that saving is not asynchronous…

(by the way, if you want to compile JSX files using Node.js, don’t install « node » on Ubuntu, that’s not « Node.js »! Install « nodejs » instead, and make a symlink from « /usr/bin/nodejs » to « node » somewhere on your path. Otherwise you may ask yourself why the JSX compiler does nothing. It’s just that the executable « node » is completely unrelated)