cleanup: Move rebuild function outside startServing function (#715)

* Move rebuild function outside `startServing`

* Move toRebuild and toRemove inside rebuild func

* Revert "Move toRebuild and toRemove inside rebuild func"

This reverts commit 8c4dbb13c7.

* Rename func to rebuildFromEntrypoint

quartz/build.ts

@@ -3,13 +3,13 @@ sourceMapSupport.install(options)
 import path from "path"
 import { PerfTimer } from "./util/perf"
 import { rimraf } from "rimraf"
-import { isGitIgnored } from "globby"
+import { GlobbyFilterFunction, isGitIgnored } from "globby"
 import chalk from "chalk"
 import { parseMarkdown } from "./processors/parse"
 import { filterContent } from "./processors/filter"
 import { emitContent } from "./processors/emit"
 import cfg from "../quartz.config"
-import { FilePath, joinSegments, slugifyFilePath } from "./util/path"
+import { FilePath, FullSlug, joinSegments, slugifyFilePath } from "./util/path"
 import chokidar from "chokidar"
 import { ProcessedContent } from "./plugins/vfile"
 import { Argv, BuildCtx } from "./util/ctx"
@@ -18,6 +18,19 @@ import { trace } from "./util/trace"
 import { options } from "./util/sourcemap"
 import { Mutex } from "async-mutex"
 
+type BuildData = {
+  ctx: BuildCtx
+  ignored: GlobbyFilterFunction
+  mut: Mutex
+  initialSlugs: FullSlug[]
+  // TODO merge contentMap and trackedAssets
+  contentMap: Map<FilePath, ProcessedContent>
+  trackedAssets: Set<FilePath>
+  toRebuild: Set<FilePath>
+  toRemove: Set<FilePath>
+  lastBuildMs: number
+}
+
 async function buildQuartz(argv: Argv, mut: Mutex, clientRefresh: () => void) {
   const ctx: BuildCtx = {
     argv,
@@ -73,19 +86,60 @@ async function startServing(
 ) {
   const { argv } = ctx
 
-  const ignored = await isGitIgnored()
   const contentMap = new Map<FilePath, ProcessedContent>()
   for (const content of initialContent) {
     const [_tree, vfile] = content
     contentMap.set(vfile.data.filePath!, content)
   }
 
-  const initialSlugs = ctx.allSlugs
-  let lastBuildMs = 0
-  const toRebuild: Set<FilePath> = new Set()
-  const toRemove: Set<FilePath> = new Set()
-  const trackedAssets: Set<FilePath> = new Set()
-  async function rebuild(fp: string, action: "add" | "change" | "delete") {
+  const buildData: BuildData = {
+    ctx,
+    mut,
+    contentMap,
+    ignored: await isGitIgnored(),
+    initialSlugs: ctx.allSlugs,
+    toRebuild: new Set<FilePath>(),
+    toRemove: new Set<FilePath>(),
+    trackedAssets: new Set<FilePath>(),
+    lastBuildMs: 0,
+  }
+
+  const watcher = chokidar.watch(".", {
+    persistent: true,
+    cwd: argv.directory,
+    ignoreInitial: true,
+  })
+
+  watcher
+    .on("add", (fp) => rebuildFromEntrypoint(fp, "add", clientRefresh, buildData))
+    .on("change", (fp) => rebuildFromEntrypoint(fp, "change", clientRefresh, buildData))
+    .on("unlink", (fp) => rebuildFromEntrypoint(fp, "delete", clientRefresh, buildData))
+
+  return async () => {
+    await watcher.close()
+  }
+}
+
+async function rebuildFromEntrypoint(
+  fp: string,
+  action: "add" | "change" | "delete",
+  clientRefresh: () => void,
+  buildData: BuildData, // note: this function mutates buildData
+) {
+  const {
+    ctx,
+    ignored,
+    mut,
+    initialSlugs,
+    contentMap,
+    toRebuild,
+    toRemove,
+    trackedAssets,
+    lastBuildMs,
+  } = buildData
+
+  const { argv } = ctx
+
   // don't do anything for gitignored files
   if (ignored(fp)) {
     return
@@ -113,7 +167,7 @@ async function startServing(
   // debounce rebuilds every 250ms
 
   const buildStart = new Date().getTime()
-    lastBuildMs = buildStart
+  buildData.lastBuildMs = buildStart
   const release = await mut.acquire()
   if (lastBuildMs > buildStart) {
     release()
@@ -159,22 +213,6 @@ async function startServing(
   clientRefresh()
   toRebuild.clear()
   toRemove.clear()
-  }
-
-  const watcher = chokidar.watch(".", {
-    persistent: true,
-    cwd: argv.directory,
-    ignoreInitial: true,
-  })
-
-  watcher
-    .on("add", (fp) => rebuild(fp, "add"))
-    .on("change", (fp) => rebuild(fp, "change"))
-    .on("unlink", (fp) => rebuild(fp, "delete"))
-
-  return async () => {
-    await watcher.close()
-  }
 }
 
 export default async (argv: Argv, mut: Mutex, clientRefresh: () => void) => {