How can I time functions in a ClojureScript Browser REPL?

Question

I have a bit of experience with Clojure, but I am new to ClojureScript. I have been working on some code that was written by someone else. It uses a browser repl in sublimetext, connected to a browser via a port and a brepl-connected.html file. I tried to time the length of a function using (time (function arg)) in the repl, but the output is 0 msecs no matter what. Why does this happen?

I've tried something like (.time js/console label), but this always returns some unintelligble object to the console.

I'd like to be able to time functions and, in general, be able to use print statements and other tools to debug and improve my code. What is the best method to do this? Should I have returns go to the repl or to the browser?

Thanks in advance, I've looked around but I can't find a good article or post explaining this.

So recently I started up my brepl, tried the standard clojure time function, and it worked... I'm not sure why. It now works almost all the time, although it occasionally starts spitting out only 0 again and I have to restart the repl. — Phylth

leeor leeor · Accepted Answer · 2016-01-21T23:56:45

This blog post explains how you can do this with a macro:

http://blog.jenkster.com/2015/09/timing-code-in-clojurescript.html

Are you wrapping your call in a .time and .timeEnd?

How can I time functions in a ClojureScript Browser REPL?

1 Answers