feat(configuration): Allow purge output folder

closes: unlight#7

README.md

@@ -114,6 +114,12 @@ with temporal dead zone when generating merged file.
 Type: `boolean`  
 Default: `false`
 
+#### `purgeOutput`
+
+Delete all files in `output` folder  
+Type: `boolean`  
+Default: `false`
+
 #### `types_*` (deprecated)
 
 <details>

prisma/schema.prisma

@@ -16,6 +16,7 @@ generator nestgraphql {
   reExport = None
   emitSingle = false
   emitCompiled = false
+  purgeOutput = false
 }
 
 model User {

src/generate.ts

@@ -1,7 +1,6 @@
 import { GeneratorOptions } from '@prisma/generator-helper';
 import { ok } from 'assert';
 import AwaitEventEmitter from 'await-event-emitter';
-import { existsSync } from 'fs';
 import { mapKeys } from 'lodash';
 import { Project, QuoteKind } from 'ts-morph';
 
@@ -15,12 +14,13 @@ import { modelData } from './handlers/model-data';
 import { modelOutputType } from './handlers/model-output-type';
 import { noAtomicOperations } from './handlers/no-atomic-operations';
 import { outputType } from './handlers/output-type';
+import { purgeOutput } from './handlers/purge-output';
 import { ReExport, reExport } from './handlers/re-export';
 import { registerEnum } from './handlers/register-enum';
 import { typeNames } from './handlers/type-names';
 import { warning } from './handlers/warning';
 import { createConfig } from './helpers/create-config';
-import { factoryGetSourceFile } from './helpers/factory-get-souce-file';
+import { factoryGetSourceFile } from './helpers/factory-get-source-file';
 import { createGetModelName } from './helpers/get-model-name';
 import { DMMF, EventArguments, Field, FieldSettings, Model, OutputType } from './types';
 
@@ -76,6 +76,7 @@ export async function generate(
     config.noAtomicOperations && noAtomicOperations(eventEmitter);
     config.reExport !== ReExport.None && reExport(eventEmitter);
     config.emitSingle && emitSingle(eventEmitter);
+    config.purgeOutput && purgeOutput(eventEmitter);
 
     const models = new Map<string, Model>();
     const modelNames: string[] = [];
@@ -108,8 +109,6 @@ export async function generate(
         getModelName: createGetModelName(modelNames),
     };
 
-    // console.dir(prismaClientDmmf.schema.outputObjectTypes, { depth: 4 });
-
     if (connectCallback) {
         await connectCallback(eventEmitter, eventArguments);
     }

src/handlers/purge-output.ts

@@ -0,0 +1,34 @@
+import AwaitEventEmitter from 'await-event-emitter';
+import { promises as fs } from 'fs';
+
+import { EventArguments } from '../types';
+
+export function purgeOutput(emitter: AwaitEventEmitter) {
+    emitter.on('Begin', begin);
+    emitter.on('End', end);
+}
+
+function begin({ project, output }: EventArguments) {
+    const sourceFiles = project.getDirectory(output)?.getDescendantSourceFiles();
+
+    if (sourceFiles) {
+        for (const sourceFile of sourceFiles) {
+            sourceFile.delete();
+        }
+    }
+}
+
+async function end({ project, output }: EventArguments) {
+    const directories = project
+        .getDirectory(output)
+        ?.getDescendantDirectories()
+        .filter(directory => directory.getSourceFiles().length === 0)
+        .map(directory => directory.getPath());
+
+    for (const directory of directories || []) {
+        try {
+            await fs.rmdir(directory);
+            // eslint-disable-next-line no-empty
+        } catch {}
+    }
+}

src/helpers/create-config.ts

@@ -82,6 +82,7 @@ export function createConfig(data: Record<string, string | undefined>) {
         emitCompiled: toBoolean(config.emitCompiled),
         $warnings,
         fields,
+        purgeOutput: toBoolean(config.purgeOutput),
     };
 }