“Falsy” vs “Falsey” – I’m Making the Call

This is probably the most asinine blog post I’ll write, but for my sanity, it must be done.

It is spelled falsy.

Without the “e” between the “s” and the “y” – priod, th nd.

Okay. So what is Falsy anyway?

In loose-typed languages like PHP or JavaScript values can be considered Boolean false if they are '' (empty strings), the number 0 (zero), NULL, and most obviously Boolean false itself, just to name a few (in PHP an empty array is considered false, while in JavaScript it is not). It is important to note that this is only in the context of non-strict comparison, i.e. == and not  ===, and when type casting to Boolean (see PHP’s type juggling reference).

When describing a false-like value it is easier/faster to type “falsy” (or the now incorrect way of “falsey”) since it has less keystrokes, and it is easier to read due to the lack of character bloat; incidentally it also fits nicely as a variable because there is no hyphen (devil’s advocate: camelCase) and it is not a reserved word. It is important that the developer does not simply describe the value as “false” since this implies a variable of type Boolean, however using “falsy” implies a false-like value of any data type which, albeit more ambiguous in its definition, is more descriptive in its context.

Supporting Data

Let’s let the data speak for a moment. After analyzing a Google Trends chart of “falsy” vs “falsey,” the results are initially a bit misleading. “Falsey” is the clear winner at first glance, only to find that there is a name and published articles with the name “Falsey.” Considering that “falsy” is not trailing by many datapoints provides the confidence that it is in use and very applicable. Most importantly in regards to the related searches, “falsy” prevails over “falsey” which does “not [have] enough search volume to show results”: “javascript falsy” and “falsy values.”

Addition: Douglas Crockford even uses “falsy” in his writing, “The Elements of JavaScript Style.” Perhaps I didn’t need to write this post after all, but I sure hope it solidifies the answer indefinitely and provides a resource for any other concerned developers out there.

Spelling Review

I am by no means an English major, or anywhere near one, but I do have a knack for research and comprehension.

With regard to the suffixation of the letter “y” (vowel) when transforming a word, the “e” is dropped per the rules:

In the word “false,” the word ends with the vowel “e,” is preceded by the consonant “s,” and none of the exceptions are applicable.

F – A – L – S – Y