Delayed startup due to slow route generation

[dmarkow]

What version of Remix are you using?

1.7.4

Steps to Reproduce

See sample repo. This sample app has a patch on the routesConvention.js file to display run time for route generation, as well as a run.js script that generates a bunch of routes and then runs remix routes. Pass an optional number for the number of route sets to create (each set has 111 routes between index/child routes). For example, node run.js 5 will profile with 5 sets of routes (556 routes including the root route). I nested the sample routes under a couple pathless routes as that seems to also decrease the performance.

# Install and run
npm i
npx patch-package
node run.js 5 | head

Expected Behavior

Ideally, performance would decrease linearly as the number of routes increases.

Actual Behavior

Exponential increase in the time it takes to run. On a fairly powerful Mac, 1 set (112 routes) takes 0.042 seconds to compile, 5 sets (556 routes) takes 3.413 seconds, and 10 sets (1,111 routes) takes 26.797 seconds.

$ node run.js 1 | head
Creating sample routes...
defineConventionalRoutes: 0.042s for 112 routes (0.38ms per file)
<Routes>
  <Route file="root.tsx">
    <Route path="0/10/0/0" index file="routes/__a/__b/__c/0/10/0/0/index.js" />
    <Route path="0/10/0/1" index file="routes/__a/__b/__c/0/10/0/1/index.js" />
    <Route path="0/10/1/0" index file="routes/__a/__b/__c/0/10/1/0/index.js" />
    <Route path="0/10/1/1" index file="routes/__a/__b/__c/0/10/1/1/index.js" />
    <Route path="0/10/2/0" index file="routes/__a/__b/__c/0/10/2/0/index.js" />
    <Route path="0/10/2/1" index file="routes/__a/__b/__c/0/10/2/1/index.js" />

$ node run.js 5 | head
Creating sample routes...
defineConventionalRoutes: 3.413s for 556 routes (6.14ms per file)
<Routes>
  <Route file="root.tsx">
    <Route path="0/10/0/0" index file="routes/__a/__b/__c/0/10/0/0/index.js" />
    <Route path="0/10/0/1" index file="routes/__a/__b/__c/0/10/0/1/index.js" />
    <Route path="0/10/1/0" index file="routes/__a/__b/__c/0/10/1/0/index.js" />
    <Route path="0/10/1/1" index file="routes/__a/__b/__c/0/10/1/1/index.js" />
    <Route path="0/10/2/0" index file="routes/__a/__b/__c/0/10/2/0/index.js" />
    <Route path="0/10/2/1" index file="routes/__a/__b/__c/0/10/2/1/index.js" />

$ node run.js 10 | head
Creating sample routes...
defineConventionalRoutes: 26.797s for 1111 routes (24.12ms per file)
<Routes>
  <Route file="root.tsx">
    <Route path="0/10/0/0" index file="routes/__a/__b/__c/0/10/0/0/index.js" />
    <Route path="0/10/0/1" index file="routes/__a/__b/__c/0/10/0/1/index.js" />
    <Route path="0/10/1/0" index file="routes/__a/__b/__c/0/10/1/0/index.js" />
    <Route path="0/10/1/1" index file="routes/__a/__b/__c/0/10/1/1/index.js" />
    <Route path="0/10/2/0" index file="routes/__a/__b/__c/0/10/2/0/index.js" />
    <Route path="0/10/2/1" index file="routes/__a/__b/__c/0/10/2/1/index.js" />

In my real world app, it's taking around 10-15 seconds to load around 700 routes (this test repo may be operating more efficiently due to short folder/route names versus the longer route paths used in my actual app). Running npm run dev has a significant delay where it seems like nothing is happening, then after 10-15 seconds the "Watching Remix app in development mode..." message finally shows up.