Support formatting generated code by Prettier

.cli.prettierignore

@@ -0,0 +1,15 @@
+tsconfig*.json
+
+build
+lib
+package
+
+coverage
+tests/artifacts
+
+.docusaurus
+
+**/prisma/generated/**/*
+**/prisma/migrations/**/*
+prisma-client-mock.js
+prisma-client-mock.d.ts

.prettierignore

@@ -1,8 +1,14 @@
 tsconfig*.json
-lib/**/*
-package/**/*
-tests/artifacts
+
+build
+lib
+package
+
 coverage
+# tests/artifacts
+
+.docusaurus
+
 **/prisma/generated/**/*
 **/prisma/migrations/**/*
 prisma-client-mock.js

docs/basics/configuration.md

@@ -50,3 +50,39 @@ generator typegraphql {
   emitTranspiledCode = true
 }
 ```
+
+## Formatting generated code
+
+By default, the generated code is formatted by TypeScript compiler while emitting.
+
+However, if you prefer some other code style, you can provide `formatGeneratedCode` generator option to format the codebase with [Prettier](https://prettier.io/):
+
+```prisma {4}
+generator typegraphql {
+  provider            = "typegraphql-prisma"
+  output              = "../prisma/generated/type-graphql"
+  formatGeneratedCode = "prettier"
+}
+```
+
+Prettier will look for the configuration file in your project tree and use it to format the generated code. If no config file detected, default settings will be applied.
+
+:::caution
+Be aware that formatting code by Prettier has a quite huge impact on the generation time, so use it with caution.
+:::
+
+If you git-ignore the generated files or you don't want to read the generated source code, you can ignore the generated code style and disable the formatting at all - by providing `false` value to `formatGeneratedCode` generator option:
+
+```prisma {4}
+generator typegraphql {
+  provider            = "typegraphql-prisma"
+  output              = "../prisma/generated/type-graphql"
+  formatGeneratedCode = false
+}
+```
+
+This way you can save even up to 33% of the generation process time.
+
+:::info
+When the generator is configured to emit transpiled code, the generated JS code is always formatted by TypeScript compiler and you can't change it to Prettier or disable the formatting by the `formatGeneratedCode` option.
+:::

experiments/postgres/prisma/generated/client/schema.prisma

@@ -24,6 +24,7 @@ generator typegraphql {
   contextPrismaKey         = "prismaClient"
   useSimpleInputs          = true
   emitRedundantTypesInfo   = true
+  formatGeneratedCode      = "tsc"
 }
 
 // Role enum comment

experiments/postgres/prisma/schema.prisma

@@ -24,6 +24,7 @@ generator typegraphql {
   contextPrismaKey         = "prismaClient"
   useSimpleInputs          = true
   emitRedundantTypesInfo   = true
+  formatGeneratedCode      = "tsc"
 }
 
 // Role enum comment

package.json

@@ -9,11 +9,11 @@
     "check:type": "tsc --noEmit",
     "check:experiments:postgres": "cd ./experiments/postgres && tsc --noEmit",
     "check:experiments:mongodb": "cd ./experiments/mongodb && tsc --noEmit",
-    "check:format": "prettier --check ./**/*.{js,json,ts,tsx}",
+    "check:format": "prettier --ignore-path ./.cli.prettierignore --check ./**/*.{js,json,ts,tsx}",
     "test": "ts-node ./tests/helpers/setup-tests.ts && jest --watch --verbose",
     "test:integration": "ts-node ./tests/helpers/setup-tests.ts && env-cmd jest --watch --verbose --config ./jest.config.integration.ts",
     "test:ci": "ts-node ./tests/helpers/setup-tests.ts && jest --coverage --verbose --runInBand && jest --coverage --verbose --runInBand --config ./jest.config.integration.ts",
-    "format": "prettier --write ./**/*.{js,json,ts,tsx}"
+    "format": "prettier --ignore-path ./.cli.prettierignore --write ./**/*.{js,json,ts,tsx}"
   },
   "bin": {
     "typegraphql-prisma": "lib/generator.js"
@@ -39,7 +39,7 @@
   "devDependencies": {
     "@jest/types": "^29.5.0",
     "@prisma/client": "~4.12.0",
-    "@prisma/fetch-engine": "4.12.0",
+    "@prisma/fetch-engine": "~4.12.0",
     "@types/graphql-fields": "^1.3.5",
     "@types/jest": "^29.5.0",
     "@types/node": "^18.15.11",

src/cli/helpers.ts

@@ -1,11 +1,15 @@
 export function parseStringBoolean(stringBoolean: string | undefined) {
-  return stringBoolean ? stringBoolean === "true" : undefined;
+  return stringBoolean === "true"
+    ? true
+    : stringBoolean === "false"
+    ? false
+    : undefined;
 }
 
 export function parseStringArray<TAllowedValue extends string>(
   stringArray: string | undefined,
   optionPropertyName: string,
-  allowedValues?: TAllowedValue[],
+  allowedValues?: readonly TAllowedValue[],
 ): TAllowedValue[] | undefined {
   if (!stringArray) {
     return undefined;
@@ -22,3 +26,19 @@ export function parseStringArray<TAllowedValue extends string>(
   }
   return parsedArray as TAllowedValue[];
 }
+
+export function parseStringEnum<TAllowedValue extends string>(
+  stringEnum: string | undefined,
+  optionPropertyName: string,
+  allowedValues: readonly TAllowedValue[],
+): TAllowedValue | undefined {
+  if (!stringEnum) {
+    return undefined;
+  }
+  if (!allowedValues.includes(stringEnum as any)) {
+    throw new Error(
+      `Invalid "${optionPropertyName}" option value "${stringEnum}" provided for TypeGraphQL generator.`,
+    );
+  }
+  return stringEnum as TAllowedValue;
+}

src/cli/prisma-generator.ts

@@ -10,7 +10,11 @@ import {
   InternalGeneratorOptions,
 } from "../generator/options";
 import { ALL_EMIT_BLOCK_KINDS } from "../generator/emit-block";
-import { parseStringBoolean, parseStringArray } from "./helpers";
+import {
+  parseStringBoolean,
+  parseStringArray,
+  parseStringEnum,
+} from "./helpers";
 
 export async function generate(options: GeneratorOptions) {
   const outputDir = parseEnvValue(options.generator.output!);
@@ -56,6 +60,13 @@ export async function generate(options: GeneratorOptions) {
       generatorConfig.omitOutputFieldsByDefault,
       "omitOutputFieldsByDefault",
     ),
+    formatGeneratedCode:
+      parseStringBoolean(generatorConfig.formatGeneratedCode) ??
+      parseStringEnum(
+        generatorConfig.formatGeneratedCode,
+        "formatGeneratedCode",
+        ["prettier", "tsc"] as const,
+      ),
   };
   const internalConfig: InternalGeneratorOptions = {
     outputDirPath: outputDir,

src/generator/generate-code.ts

@@ -1,6 +1,9 @@
 import { DMMF as PrismaDMMF } from "@prisma/client/runtime";
 import { Project, ScriptTarget, ModuleKind, CompilerOptions } from "ts-morph";
 import path from "path";
+import { exec } from "node:child_process";
+import { promisify } from "node:util";
+const execa = promisify(exec);
 
 import { noop, toUnixPath } from "./helpers";
 import generateEnumFromDef from "./enum";
@@ -76,6 +79,7 @@ export default async function generateCode(
       baseOptions.prismaClientPath.includes("node_modules")
         ? "@prisma/client"
         : undefined,
+    formatGeneratedCode: baseOptions.formatGeneratedCode ?? "tsc", // default for backward compatibility
   };
 
   const baseDirPath = options.outputDirPath;
@@ -527,9 +531,14 @@ export default async function generateCode(
   if (emitTranspiledCode) {
     await project.emit();
   } else {
-    for (const file of project.getSourceFiles()) {
-      file.formatText({ indentSize: 2 });
+    if (options.formatGeneratedCode === "tsc") {
+      for (const file of project.getSourceFiles()) {
+        file.formatText({ indentSize: 2 });
+      }
     }
     await project.save();
+    if (options.formatGeneratedCode === "prettier") {
+      await execa(`npx prettier --write ${baseDirPath}`);
+    }
   }
 }

src/generator/options.ts

@@ -14,6 +14,7 @@ export interface ExternalGeneratorOptions {
   useSimpleInputs?: boolean;
   omitInputFieldsByDefault?: string[];
   omitOutputFieldsByDefault?: string[];
+  formatGeneratedCode?: boolean | "prettier" | "tsc";
 }
 
 export interface InternalGeneratorOptions {