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ES2021 edition of “JavaScript for impatient programmers”

What is new in the ES2021 edition of “JavaScript for impatient programmers”?

Free to read online: exploringjs.com/impatient-js/

  • The exercises now run as native ESM modules on Node.js. Previously, they were run via the esm package.
  • Material on new ES2021 features:
    • String.prototype.replaceAll()
    • Promise.any()
    • Logical assignment operators
    • Underscores (_) as separators in number literals and bigint literals
  • New chapter: “New JavaScript features” lists what’s new in each release after ES6.
  • Describing some features in more detail:
    • ES2019: New section on optional catch binding
    • ES2019: New section on Symbol.prototype.description
    • ES2018: New section on the template literal revision
    • ES2018: New section on Promise.prototype.finally()
    • ES2017: New section on trailing commas in function parameter lists and calls
  • Rewrite of chapter “Callable values”:
    • Moved content on dynamic code evaluation into its own chapter.
    • Improved coverage of this
    • And more
  • Rewrite of chapter “Single objects”:
    • Improved coverage of this
    • Explaining the function methods .call(), .apply(), .bind()
  • Chapter on symbols:
    • Mostly new section “Symbols are primitives that are also like objects”
    • New section “The descriptions of symbols”
    • Major rewrite of section “Symbols as unique property keys”
  • Chapter on regular expressions:
    • Much improved section “The flags /g and /y, and the property .lastIndex
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