feat(generator): use prettier if present (#1222)

package.json

@@ -132,10 +132,11 @@
     "@dprint/formatter": "^0.4.0",
     "@dprint/typescript": "^0.93.0",
     "@opentelemetry/api": "^1.9.0",
-    "graphql": "14 - 16"
+    "graphql": "14 - 16",
+    "prettier": "^3.3.3"
   },
   "peerDependenciesMeta": {
-    "dprint": {
+    "prettier": {
       "optional": true
     },
     "@opentelemetry/api": {
@@ -168,6 +169,7 @@
     "@typescript-eslint/parser": "^8.11.0",
     "async-cleanup": "^1.0.0",
     "doctoc": "^2.2.1",
+    "dprint": "^0.47.4",
     "dripip": "^0.10.0",
     "es-toolkit": "^1.26.1",
     "eslint": "^9.13.0",
@@ -188,6 +190,7 @@
     "graphql-upload-minimal": "^1.6.1",
     "graphql-yoga": "^5.7.0",
     "jsdom": "^25.0.1",
+    "prettier": "^3.3.3",
     "publint": "^0.2.12",
     "strip-ansi": "^7.1.0",
     "tsx": "^4.19.1",

src/lib/typescript-formatter.ts

@@ -10,21 +10,36 @@ export const passthroughFormatter: Formatter = {
   formatText: (content) => Promise.resolve(content),
 }
 
+export const getTypeScriptFormatter = async (): Promise<Formatter | null> => {
+  return await getTypeScriptFormatterDprint() ?? await getTypeScriptFormatterPrettier()
+}
+
+export const getTypeScriptFormatterPrettier = async (): Promise<Formatter | null> => {
+  try {
+    const prettier = await import(`prettier`)
+    return {
+      formatText: (content) => prettier.format(content, { parser: `typescript` }),
+    }
+  } catch (error) {
+    return null
+  }
+}
+
 /**
  * Attempt to get a TypeScript formatter using dynamic imports. If none succeed then returns null.
  *
  * This allows users to bring their own formatters (within an allow list of what we try to dynamically import).
  */
-export const getTypeScriptFormatter = async (): Promise<Formatter | null> => {
+export const getTypeScriptFormatterDprint = async (): Promise<Formatter | null> => {
   try {
     const { createFromBuffer } = await import(`@dprint/formatter`)
     const { getPath } = await import(`@dprint/typescript`)
     const formatter = createFromBuffer(await fs.readFile(getPath()))
+    // todo handle failing to read configuration file gracefully. Don't swallow those errors.
+    // TODO don't read config file manually? https://github.com/dprint/js-formatter/issues/13
+    const localConfig = await readJsonFile<{ typescript?: JsonObject }>(`dprint.json`) ?? {}
     return {
       formatText: async (fileText, customFormatterConfig) => {
-        // todo handle failing to read configuration file gracefully.
-        // TODO don't read config file manually? https://github.com/dprint/js-formatter/issues/13
-        const localConfig = await readJsonFile<{ typescript?: JsonObject }>(`dprint.json`) ?? {}
         const overrideConfig = {
           ...localConfig.typescript,
           ...customFormatterConfig,

tests/e2e/e2e.test.ts

@@ -87,3 +87,16 @@ test(`client uses dprint formatter if installed`, async ({ project }) => {
 
   await project.run`pnpm dprint check graffle/**/*`
 })
+
+test(`client uses prettier formatter if installed`, async ({ project }) => {
+  // await project.addDprintConfig()
+  const path = await project.addPokemonSchemaSDL()
+
+  await project.run`pnpm add --save-dev prettier`
+
+  const genResult = await project.run`pnpm graffle --schema ${path.relative} --format`
+  const genResultStdout = genResult.stdout as string
+  expect(genResultStdout.includes(`No TypeScript formatter found`)).toEqual(false)
+
+  await project.run`pnpm prettier --check graffle/**/*`
+})