console.timeLog

I work on a really complex debugger at Mozilla but, and don't tell my colleagues, I sometimes enjoy simply using console.log and other console commands to get some simple output.  I know, I know, but hey -- whatever gets the job done.  A few years ago I detailed console.time and console.timeEnd for measuring time for a given set of tasks; let me show you console.timeLog, a new function in Firefox Nightly for logging events during a console.time timer!

Start by kicking off the timer with a name of your choice:

console.time("MyApp");

Whenever you want the intermediate timer value, as well as extra information like variable or object values, you can use console.timeLog:

// Same timer name, provide sublabel and optional info
console.timeLog("MyApp", "constructor"); 
// MyApp: 4ms constructor

console.timeLog("MyApp", "render", this.state);
// MyApp: 2ms render Object { disabled: false }

When your timed tasks have completed, you can call console.timeEnd to stop the timer:

console.timeEnd("MyApp");
// MyApp: 10ms

Firefox has a Performance tab for very detailed performance metrics but, as always, the console is a great way to get some basic insight at a glance.  The timeLog function is an awesome way to get intermediate timing and information while your script runs!