Commits on Dec 20, 2020

1. Replace Babel w/ estree …

   This removes the last three custom Babel plugins we had and replaces
   them with estree versions.
   Furthermore, it removes `@babel/generator`.
   
   For the plugins, we were only looking at ESM import/exports, but right
   now we’re delegating work to `periscopic` to look at which things are
   defined in the top-level scope.
   It’s a bit more complex, but this matches better with intentions,
   fixes some bugs, and prepares for a potential future where other ES
   constructs are allowed, so all in all should be a nice improvement.
   
   For serializing, we’re switching to `astring`, and handling JSX for now
   internally (could be externalized later).
   `astring` seems fast and is incredibly small, but is not very popular.
   We might perhaps see bugs is serialization in the future because of that,
   but all our tests seem fine, so I’m not too worried about that.
   
   Estree remains a somewhat fragmented ecosystem, such as that the tree
   walkers in `periscopic` and `astring` are different, so we might also
   consider writing our own serializer in the future.
   Or, when we implement Babel’s React JSX transform ourselves, could switch
   to another generator, or at least drop the JSX serialization code here.
   
   Because of these changes, we can drop `@babel/core` and
   `@babel/generator` from `@mdx-js/mdx`, which drops the bundle size of
   from 349kb to 111kb.
   That’s 68%.
   Pretty nice.
   This should improve downloading and parsing time of bundles
   significantly.
   Of course, we currently still have JSX in the output, so folks will
   have to resort to Babel (or `buble-jsx-only`) in another step.
   
   For performance, v2 (micromark) was already an improvement over v1.
   On 1000 simple files totalling about 1mb of MDX:
   
   * v1: 3739ms
   * v2: 2734ms (26% faster)
   * v2 (w/o babel): 1392ms (63% faster).
   
   Of course, this all really depends on what type of stuff is in your MDX.
   But it looks pretty sweet!
   
   ✨
   
   Related to GH-1046.
   Related to GH-1152.
   Related to GH-1338.
   Closes GH-704.
   Closes GH-1384.

   

   wooorm committed Dec 20, 2020
   Configuration menu

   • View commit details
   • Copy full SHA for eed6cf4
   • Browse repository at this point

   Copy the full SHA

   eed6cf4 View commit details

   Browse the repository at this point in the history