Learning JavaScript Design Patterns, 2nd Edition

Chapter 2. “Pattern”-ity Testing, Proto-Patterns, and the Rule of Three

From the moment a new pattern is proposed to its potential widespread adoption, a pattern may have to go through multiple rounds of deep inspection by the design community and software developers. This chapter talks about this journey of a newly introduced “proto-pattern” through a “pattern”-ity test until it is eventually recognized as a pattern if it meets the rule of three.

This and the next chapter explore the approach to structuring, writing, presenting, and reviewing nascent design patterns. If you’d prefer to learn established design patterns first, you can skip these two chapters for the time being.

What Are Proto-Patterns?

Remember that not every algorithm, best practice, or solution represents what might be considered a complete pattern. There may be a few key ingredients missing, and the pattern community is generally wary of something claiming to be one without an extensive and critical evaluation. Even if something is presented to us which appears to meet the criteria for a pattern, we should not consider it as one until it has undergone suitable periods of scrutiny and testing by others.

Looking back upon Alexander’s work once more, he claims that a pattern should be both a process and a “thing.” This definition is obtuse as he follows by saying that it is the process that should create the “thing.” This is why patterns generally focus on addressing a visually identifiable structure; we should ...