JavaScript Efficiencies

I'm working on an article about patterns for structuring Express.JS apps, which is taking too long, so I decided to write this instead: Here are a few tips and tricks for JavaScript programming that I like.

Comment switches

Comment switches let you comment out entire blocks of code with a single character, or switch between two different blocks of code with a single character, which can be useful when prototyping.

//* 
console.log("Hello!\n"); 
/*/  
console.log("Goodbye!\n"); 
// */

Removing the first slash '/' toggles between these two print statements. See the original post for more examples of comment switches.

Iterate by Counting Down

You can iterate n times concisely, like this:

var n = 1000;
while (n--) { ... }

Defaulting Arguments

This is a handy way to provide a default value for undefined arguments in a JavaScript function.

function foo(bar) {
   var bar = bar || "Some default";
   ...
}