This is a good advice for those who just graduated college and/or for those who are just starting a career in programming. Because that was my experience. I focused on one thing so I can earn a living out of it.
But if the point of this article is about LEARNING, then I totally disagree. People learn differently. There are those who learn more and faster by hacking into different technologies, frameworks, languages, etc. And that includes me. Until now, it continuously improves my ability to adapt to a new technology, language, and start working on it fast. My employer commended me for that. They threw me to different projects and I can work on it. They're happy about it.
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