vercel og ast rules

Author: james-elicx

packages/cloudflare/src/cli/build/patches/ast/vercel-og.spec.ts

@@ -0,0 +1,26 @@
+import { describe, expect, it } from "vitest";
+
+import { patchCode } from "./util";
+import { vercelOgFallbackFontRule, vercelOgImportRule } from "./vercel-og";
+
+describe("vercelOgImportRule", () => {
+  it("should rewrite a node import to an edge import", () => {
+    const code = `e.exports=import("next/dist/compiled/@vercel/og/index.node.js")`;
+    expect(patchCode(code, vercelOgImportRule)).toMatchInlineSnapshot(
+      `"e.exports=import("next/dist/compiled/@vercel/og/index.edge.js")"`
+    );
+  });
+});
+
+describe("vercelOgFallbackFontRule", () => {
+  it("should replace a fetch call for a font with an import", () => {
+    const code = `var fallbackFont = fetch(new URL("./noto-sans-v27-latin-regular.ttf", import.meta.url)).then((res) => res.arrayBuffer());`;
+    expect(patchCode(code, vercelOgFallbackFontRule)).toMatchInlineSnapshot(`
+      "async function getFallbackFont() {
+        return (await import("./noto-sans-v27-latin-regular.ttf.bin")).default
+      }
+
+      var fallbackFont = getFallbackFont()"
+    `);
+  });
+});

packages/cloudflare/src/cli/build/patches/ast/vercel-og.ts

@@ -0,0 +1,51 @@
+import { SgNode } from "@ast-grep/napi";
+
+import { applyRule } from "./util.js";
+
+export const vercelOgImportRule = `
+rule:
+  pattern: $NODE
+  kind: string
+  regex: "next/dist/compiled/@vercel/og/index.node.js"
+inside:
+  kind: arguments
+  inside:
+    kind: call_expression
+    stopBy: end
+    has:
+      field: function
+      regex: "import"
+
+fix: |-
+  "next/dist/compiled/@vercel/og/index.edge.js"
+`;
+
+export function patchVercelOgImport(root: SgNode) {
+  return applyRule(vercelOgImportRule, root);
+}
+
+export const vercelOgFallbackFontRule = `
+rule:
+  kind: variable_declaration
+  all:
+    - has:
+        kind: variable_declarator
+        has:
+          kind: identifier
+          regex: ^fallbackFont$
+    - has:
+        kind: call_expression
+        pattern: fetch(new URL("$PATH", $$$REST))
+        stopBy: end
+
+fix: |-
+  async function getFallbackFont() {
+    return (await import("$PATH.bin")).default
+  }
+
+  var fallbackFont = getFallbackFont()
+`;
+
+export function patchVercelOgFallbackFont(root: SgNode) {
+  return applyRule(vercelOgFallbackFontRule, root);
+}