As an engineer, I assume you use a programming language and the libraries from its ecosystem to solve problems. Unless the latest features are essential to solving your problems, I would say this is unnecessary worry.
We use both ES5 and ES6 (via transpilation) where I work. I had to write a lot of the tooling to support ES6 because a lot of front-end engineers were asking for ES6. To this day, I have yet to hear one engineer justify their "need" for ES6 with one of the features that make something easy that is hard or cumbersome with ES5. Pretty much every feature engineers were wanting to use were simple sugary syntax features like the spread operator that is trivially dealt with with a library like `xtend` (the irony is seeing these same engineers continue to use _.each on arrays instead of Array.prototype.forEach)
In any debate on the merits of migrating to ES6, the
total number of times an ES6 feature is cited as
justification to migrate to ES6 is proportional to two
raised to the power of its position.
0. Semantic features
1. Syntax features
2. Lexical syntax features
3. Lexical syntax of comments features
We use both ES5 and ES6 (via transpilation) where I work. I had to write a lot of the tooling to support ES6 because a lot of front-end engineers were asking for ES6. To this day, I have yet to hear one engineer justify their "need" for ES6 with one of the features that make something easy that is hard or cumbersome with ES5. Pretty much every feature engineers were wanting to use were simple sugary syntax features like the spread operator that is trivially dealt with with a library like `xtend` (the irony is seeing these same engineers continue to use _.each on arrays instead of Array.prototype.forEach)
There is a corollary to Wadler's Law in here somewhere: https://wiki.haskell.org/Wadler's_Law