Bridging the tooling gap with Scala.js

Scala.js is a tool for compiling your Scala code to JavaScript. This enables writing type-safe and robust front-end application, but have you ever considered what it can do for Scala tooling? In this talk we’ll see how Scala.js can bridge the gap between the Scala-based and the JavaScript-based tools we use every day as programmers.

Transcript

1. Bridging the
   tooling gap
   with Scala.js
   

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2. me, hi!
   

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3. stuff I do
   

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4. Let's talk about JavaScript
   

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5. '' == false // true
   [''] == '' // true
   [[]] == 0 // true
   typeof document.all // undefined
   document.all === undefined // false
   document.all === null // false
   document.all == null // true
   Number.MIN_VALUE > 0 // true
   ['1','2','3'].map(parseInt) // [1, NaN, NaN]
   

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6. Built with JS
   desktop apps
   

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7. Built with JS
   mobile apps
   

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8. Built with JS
   backends
   

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9. Oh, right, and the
   

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10. It matters
    (like it or not)
    

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11. A story
    

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12. Mythical Trees
    and where to find them
    

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13. AST Explorer
    

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15. First idea
    +-------------------------+ +------------------------+
    | | | |
    | | | |
    | | | |
    | | source | |
    | +---------------------------------------> | |
    | | | |
    | | | |
    | | | |
    | AST EXPLORER | | JVM SERVER |
    | | | |
    | | AST | (SCALAMETA) |
    | | <---------------------------------------+ |
    | | | |
    | | | |
    | | | |
    | | | |
    | | | |
    | | | |
    | | | |
    | | | |
    +-------------------------+ +------------------------+
    

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16. downsides
    4 loading time
    4 extra infra
    

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17. Write a parser from scratch
    

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18. Scala.js?
    

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19. Scala.js!
    

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21. Benefits
    4
    !
    fast
    4
    ☁
    no extra infra
    demo
    

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22. Fast forward a few weeks
    

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24. First idea
    +-------------------------+ +------------------------+
    | | | |
    | | | |
    | | | |
    | | source | |
    | +---------------------------------------> | |
    | | | |
    | | | |
    | | | |
    | VSCODE | | SCALAFMT CLI |
    | | | |
    | | formatted source | (JVM) |
    | | <---------------------------------------+ |
    | | | |
    | | | |
    | | | |
    | | | |
    | | | |
    | | | |
    | | | |
    | | | |
    +-------------------------+ +------------------------+
    

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25. Downsides
    4
    !
    slow (for a single file)
    4
    "
    not self-contained
    

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26. Scala.js?
    

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27. Yep
    

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28. Upsides
    4
    !
    fast
    4
    "
    self-contained
    Downsides
    4
    !
    config -> cross-platform HOCON is still meh
    

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29. Free ideas, grab them!
    4 scalafmt on astexplorer.net
    4 (alternatively) standalone playground on
    scalafmt.org
    4 browser extension that formats code comments
    4 scalafmt on scala native
    4 GitHub app for scalafmt checks (talk to
    @laughedelic)
    

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30. Thanks
    

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