Migrated to faster PostCSS v8 API - thanks @ai

src/core/declProcessor.js

@@ -85,7 +85,14 @@ function buildResult(newUrl, matched, before, after) {
   return `${before}${newUrl}${after}`
 }
 
+// Tracks visited declarations
+const processTracker = new Set()
+
 export const declProcessor = (from, to, options, result, decl) => {
+  if (processTracker.has(decl)) {
+    return
+  }
+
   const dir = { from, to, file: getDirDeclFile(decl) }
   const pattern = /(url\(\s*["']?)([^"')]+)(["']?\s*\))/g
 
@@ -120,6 +127,7 @@ export const declProcessor = (from, to, options, result, decl) => {
       return null
     })
   ).then((values) => {
+    processTracker.add(decl)
     decl.value = decl.value.replace(pattern, (match) => {
       const replacement = values.shift()
       return replacement == null ? match : replacement

src/index.js

@@ -1,25 +1,19 @@
 import path from "path"
 
-import { Once } from "postcss"
+import { Declaration } from "postcss"
 
 import { declProcessor } from "./core/declProcessor"
 
 export default (options = {}) => ({
-    postcssPlugin: "postcss-dark-theme-class",
-    Once(root, { result }) {
-      const opts = result.opts
-      const from = opts.from ? path.dirname(opts.from) : "."
-      const to = opts.to ? path.dirname(opts.to) : from
+  postcssPlugin: "postcss-smart-asset",
+  Declaration(decl, { result }) {
+    const opts = result.opts
+    const from = opts.from ? path.dirname(opts.from) : "."
+    const to = opts.to ? path.dirname(opts.to) : from
 
-      const promises = []
+    return declProcessor(from, to, options, result, decl)
+  }
+})
 
-      root.walkDecls((decl) => {
-        promises.push(declProcessor(from, to, options, result, decl))
-      })
-
-      return Promise.all(promises)
-    }
-  })
-
-// PostCSS v8
+// PostCSS v8 marker
 export const postcss = true

src/mode/rebase.test.js

@@ -5,9 +5,8 @@ import { compareFixtures, processedCss } from "../../test/setup"
 describe("rebase", () => {
   const opts = {}
 
-  test("rebase with empty options", () => {
-    processedCss("copy-hash", undefined, { from: "test/fixtures/here" })
-  })
+  test("rebase with empty options", () =>
+    processedCss("copy-hash", undefined, { from: "test/fixtures/here" }))
 
   compareFixtures("cant-rebase", "shouldn't rebase url if not info available")
   compareFixtures("rebase-to-from", "should rebase url to dirname(from)", opts, {

tsconfig.json

@@ -1,4 +1,5 @@
 {
+  "include": ["src"],
   "lib": ["dom", "dom.iterable", "esnext"],
   "allowJs": true,
   "skipLibCheck": true,