ECMAScript 2018: the final feature set

Check out my book (free online): “Exploring ES2018 and ES2019”. Buy it now and get all future updates.

The feature set of ECMAScript 2018 was finalized during the latest TC39 meeting (23-25 January 2018). This blog post describes it.

A word on ECMAScript versions  #

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.

The features of ES2018  #

Major new features:

• Asynchronous Iteration (Domenic Denicola, Kevin Smith)
• Rest/Spread Properties (Sebastian Markbåge)

New regular expression features:

• RegExp named capture groups (Gorkem Yakin, Daniel Ehrenberg)
• RegExp Unicode Property Escapes (Mathias Bynens)
• RegExp Lookbehind Assertions (Gorkem Yakin, Nozomu Katō, Daniel Ehrenberg)
• s (dotAll) flag for regular expressions (Mathias Bynens)

Other new features:

• Promise.prototype.finally() (Jordan Harband)
• Template Literal Revision (Tim Disney)

FAQ  #

Is there an official list of ECMAScript features?  #

Yes, the TC39 repo lists finished proposals and mentions in which ECMAScript versions they are introduced.

What do the stages mean?  #

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.

How is [my favorite proposed feature] doing?  #

If you are wondering what stages various proposed features are in, consult the readme of the ECMA-262 GitHub repository.

Further reading  #

The following books of mine are free to read online:

• ECMAScript 5: “Speaking JavaScript”
• ECMAScript 6: “Exploring ES6”
• ECMAScript 2016 & 2017: “Exploring ES2016 and ES2017”
• ECMAScript 2018 & 2019: “Exploring ES2018 and ES2019”