feat(api): export SDK (#856)

* feat(api): export SDK

In some use cases, the SDK class needs to be instantiated several
times.

For instance, in a multi-tenancy scenario, there may be multiple
instances of the same API server, but serving different data from
different base URLs. In this case, we need to instantiate multiple
clients with different server URLs.

* fix(api): export sdk in a separate file

---------

Co-authored-by: Kanad Gupta <8854718+kanadgupta@users.noreply.github.com>

Author: yoitsro

packages/api/src/codegen/languages/typescript/index.ts

@@ -210,6 +210,7 @@ export default class TSGenerator extends CodeGenerator {
   async generate() {
     const srcDirectory = this.project.createDirectory('src');
     const sdkSource = this.createSDKSource(srcDirectory);
+    this.createIndexSource(srcDirectory);
 
     this.createGitIgnore();
     this.createPackageJSON();
@@ -278,14 +279,32 @@ export default class TSGenerator extends CodeGenerator {
     return snippet;
   }
 
+  /**
+   * Create our main `index.ts` file that will be the entrypoint for our SDK.
+   * This file will be used to export the SDK and any types that are generated.
+   *
+   */
+  private createIndexSource(sourceDirectory: Directory) {
+    const sourceFile = sourceDirectory.createSourceFile('index.ts', '');
+
+    sourceFile.addImportDeclaration({
+      defaultImport: 'SDK',
+      moduleSpecifier: './sdk.js',
+    });
+
+    this.createSDKExport(sourceFile);
+
+    return sourceFile;
+  }
+
   /**
    * Create our main SDK source file.
    *
    */
   private createSDKSource(sourceDirectory: Directory) {
     const { operations } = this.loadOperationsAndMethods();
 
-    const sourceFile = sourceDirectory.createSourceFile('index.ts', '');
+    const sourceFile = sourceDirectory.createSourceFile('sdk.ts', '');
 
     sourceFile.addImportDeclarations([
       // This import will be automatically removed later if the SDK ends up not having any types.
@@ -302,6 +321,8 @@ export default class TSGenerator extends CodeGenerator {
     this.sdk = sourceFile.addClass({
       name: 'SDK',
       properties: [{ name: 'core', type: 'APICore' }],
+      isDefaultExport: true,
+      isExported: true,
     });
 
     this.sdk.addConstructor({
@@ -405,8 +426,6 @@ sdk.server('https://eu.api.example.com/v14');`),
       this.createOperationAccessor(data.operation, operationId, data.types.params, data.types.responses);
     });
 
-    this.createSDKExport(sourceFile);
-
     return sourceFile;
   }
 
@@ -595,6 +614,7 @@ dist/
       dts: true,
       entry: [
         './src/index.ts',
+        './src/sdk.ts',
         // If this SDK has schemas and generated types then we should also export those too so
         // they're available to use.
         hasTypes ? './src/types.ts' : '',
@@ -626,6 +646,10 @@ dist/
           import: './dist/index.js',
           require: './dist/index.cjs',
         },
+        './sdk': {
+          import: './dist/sdk.js',
+          require: './dist/sdk.cjs',
+        },
         ...(hasTypes
           ? {
               './types': {

packages/test-utils/sdks/alby/package.json

@@ -10,6 +10,10 @@
       "import": "./dist/index.js",
       "require": "./dist/index.cjs"
     },
+    "./sdk": {
+      "import": "./dist/sdk.js",
+      "require": "./dist/sdk.cjs"
+    },
     "./types": {
       "import": "./dist/types.js",
       "require": "./dist/types.cjs"
@@ -36,6 +40,7 @@
     "dts": true,
     "entry": [
       "./src/index.ts",
+      "./src/sdk.ts",
       "./src/types.ts"
     ],
     "format": [