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The feature set of ECMAScript 2018 was finalized during the latest TC39 meeting (23-25 January 2018). This blog post describes it.
Note that since the TC39 process was instituted, the importance of ECMAScript versions has much decreased. What really matters now is what stage a proposed feature is in: Once it has reached stage 4, it can be used safely. But even then, you still have to check if your engines of choice support it.
Major new features:
New regular expression features:
dotAll) flag for regular expressions (Mathias Bynens)
Other new features:
Yes, the TC39 repo lists finished proposals and mentions in which ECMAScript versions they are introduced.
They refer to maturity stages of the so-called “TC39 process”. Check chapter “The TC39 process for ECMAScript features” in “Exploring ES2016 and ES2017” for more information.
If you are wondering what stages various proposed features are in, consult the readme of the ECMA-262 GitHub repository.
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