fix: Return this if already loaded

src/__tests__/loader.test.ts

@@ -5,7 +5,7 @@
  * currently not supported in the browser lib).
  */
 
-import posthog from '../loader-module'
+import posthog, { PostHog } from '../loader-module'
 import sinon from 'sinon'
 import { window } from '../utils/globals'
 
@@ -48,4 +48,22 @@ describe(`Module-based loader in Node env`, () => {
     it(`supports capture()`, () => {
         expect(() => posthog.capture(`Pat`)).not.toThrow()
     })
+
+    it(`always returns posthog from init`, () => {
+        console.error = jest.fn()
+        console.warn = jest.fn()
+        expect(posthog.init(`my-test`, undefined, 'sdk-1')).toBeInstanceOf(PostHog)
+        expect(posthog.init(``, undefined, 'sdk-2')).toBeInstanceOf(PostHog)
+        expect(console.error).toHaveBeenCalledTimes(1)
+        expect(console.error).toHaveBeenCalledWith(
+            '[PostHog.js]',
+            'PostHog was initialized without a token. This likely indicates a misconfiguration. Please check the first argument passed to posthog.init()'
+        )
+        // Already loaded
+        expect(posthog.init(`my-test`, undefined, 'sdk-1')).toBeInstanceOf(PostHog)
+        expect(console.warn).toHaveBeenCalledWith(
+            '[PostHog.js]',
+            'You have already initialized PostHog! Re-initializing is a no-op'
+        )
+    })
 })

src/posthog-core.ts

@@ -273,7 +273,7 @@ export class PostHog {
      */
     init(token: string, config?: Partial<PostHogConfig>, name?: string): PostHog | void {
         if (!name || name === PRIMARY_INSTANCE_NAME) {
-            // This means we are initialising the primary instance (i.e. this)
+            // This means we are initializing the primary instance (i.e. this)
             return this._init(token, config, name)
         } else {
             const namedPosthog = instances[name] ?? new PostHog()
@@ -299,17 +299,17 @@ export class PostHog {
     // IE11 compatible. We could use polyfills, which would make the
     // code a bit cleaner, but will add some overhead.
     //
-    _init(token: string, config: Partial<PostHogConfig> = {}, name?: string): PostHog | void {
+    _init(token: string, config: Partial<PostHogConfig> = {}, name?: string): PostHog {
         if (_isUndefined(token) || _isEmptyString(token)) {
             logger.critical(
                 'PostHog was initialized without a token. This likely indicates a misconfiguration. Please check the first argument passed to posthog.init()'
             )
-            return
+            return this
         }
 
         if (this.__loaded) {
-            logger.warn('You have already initialized PostHog! Re-initialising is a no-op')
-            return
+            logger.warn('You have already initialized PostHog! Re-initializing is a no-op')
+            return this
         }
 
         this.__loaded = true