Programming Languages Are Tools, Not Identities

Don't think of yourself as a Javascript Developer or a Ruby Developer or a Python developer. Think of yourself as someone who often uses one or more programming languages as a tool to solve problems.

You will likely have languages you prefer and will develop a sense of what languages will work better for different situations. These feelings can help you push for certain languages to be used but you won't always be able to use your favorite tools for every project. By thinking of languages as tools that you have developed informed opinions about rather than part of your core identity you make yourself much more versatile.

Your knowledge of your favorite language should make it easier to learn new languages. Now you can understand the new language by comparing and contrasting its paradigms with those you already know well.

The same goes for frameworks and other technologies.