From 9ecab4d5b2af6c984eacd4f7471a136b7cdea5ec Mon Sep 17 00:00:00 2001
From: Ahmet Yesil <yesil.ahmet@ing.com>
Date: Tue, 4 Aug 2020 13:42:20 +0200
Subject: [PATCH] chore: remove LionSingleton

---
 .changeset/silver-rice-applaud.md             |   9 ++
 packages/ajax/README.md                       |   8 +-
 packages/ajax/src/AjaxClass.js                |   5 +-
 packages/ajax/src/ajax.js                     |   2 +-
 .../ajax/test/AjaxClass.interceptors.test.js  |  20 +--
 packages/ajax/test/AjaxClass.test.js          |  46 ++++---
 .../ajax/test/AjaxClass.transformers.test.js  |  20 +--
 packages/core/index.js                        |   1 -
 packages/core/src/LionSingleton.js            |  51 -------
 packages/core/test/LionSingleton.test.js      | 126 ------------------
 packages/icon/src/IconManager.js              |   8 +-
 packages/icon/src/icons.js                    |   2 +-
 packages/localize/src/LocalizeManager.js      |   4 +-
 packages/localize/src/localize.js             |   2 +-
 .../localize/test/LocalizeManager.test.js     |   3 +-
 packages/localize/test/localize.test.js       |   6 -
 16 files changed, 70 insertions(+), 243 deletions(-)
 create mode 100644 .changeset/silver-rice-applaud.md
 delete mode 100644 packages/core/src/LionSingleton.js
 delete mode 100644 packages/core/test/LionSingleton.test.js

diff --git a/.changeset/silver-rice-applaud.md b/.changeset/silver-rice-applaud.md
new file mode 100644
index 000000000..2ed7870cd
--- /dev/null
+++ b/.changeset/silver-rice-applaud.md
@@ -0,0 +1,9 @@
+---
+'@lion/ajax': minor
+'@lion/core': minor
+'@lion/icon': minor
+'@lion/localize': minor
+---
+
+Removing LionSingleton as es modules are already guaranteed to be singletons.
+This reduces complexity and means less code to ship to our users.
diff --git a/packages/ajax/README.md b/packages/ajax/README.md
index 2cfd3b6f3..20d73b7e4 100644
--- a/packages/ajax/README.md
+++ b/packages/ajax/README.md
@@ -91,7 +91,7 @@ This prefix should be stripped before parsing the string as JSON.
 Pass the prefix with the `jsonPrefix` option.
 
 ```js
-const myAjax = AjaxClass.getNewInstance({ jsonPrefix: ")]}'," });
+const myAjax = new AjaxClass({ jsonPrefix: ")]}'," });
 myAjax
   .get('./packages/ajax/docs/assets/data.json')
   .then(response => {
@@ -110,7 +110,7 @@ Add additional headers to the requests with the `headers` option.
 export const additionalHeaders = () => html`
   <button
     @click=${() => {
-      const myAjax = AjaxClass.getNewInstance({ headers: { 'MY-HEADER': 'SOME-HEADER-VALUE' } });
+      const myAjax = new AjaxClass({ headers: { 'MY-HEADER': 'SOME-HEADER-VALUE' } });
       myAjax
         .get('./packages/ajax/docs/assets/data.json')
         .then(response => {
@@ -136,7 +136,7 @@ It is possible to make an Ajax request cancelable, and then call `cancel()` to m
 export const cancelableRequests = () => html`
   <button
     @click=${() => {
-      const myAjax = AjaxClass.getNewInstance({ cancelable: true });
+      const myAjax = new AjaxClass({ cancelable: true });
       requestAnimationFrame(() => {
         myAjax.cancel('too slow');
       });
@@ -163,7 +163,7 @@ You can cancel concurrent requests with the `cancelPreviousOnNewRequest` option.
 export const cancelConcurrentRequests = () => html`
   <button
     @click=${() => {
-      const myAjax = AjaxClass.getNewInstance({ cancelPreviousOnNewRequest: true });
+      const myAjax = new AjaxClass({ cancelPreviousOnNewRequest: true });
       myAjax
         .get('./packages/ajax/docs/assets/data.json')
         .then(response => {
diff --git a/packages/ajax/src/AjaxClass.js b/packages/ajax/src/AjaxClass.js
index 345ed1616..42b18366e 100644
--- a/packages/ajax/src/AjaxClass.js
+++ b/packages/ajax/src/AjaxClass.js
@@ -1,5 +1,4 @@
 import { axios } from '@bundled-es-modules/axios';
-import { LionSingleton } from '@lion/core';
 import {
   cancelInterceptorFactory,
   cancelPreviousOnNewRequestInterceptorFactory,
@@ -11,7 +10,7 @@ import { jsonPrefixTransformerFactory } from './transformers.js';
  * `AjaxClass` creates the singleton instance {@link:ajax}. It is a promise based system for
  * fetching data, based on [axios](https://github.com/axios/axios).
  */
-export class AjaxClass extends LionSingleton {
+export class AjaxClass {
   /**
    * @property {Object} proxy the axios instance that is bound to the AjaxClass instance
    */
@@ -28,8 +27,6 @@ export class AjaxClass extends LionSingleton {
    * @param {string} config.cancelPreviousOnNewRequest prevents concurrent requests
    */
   constructor(config) {
-    super();
-
     this.__config = {
       lang: document.documentElement.getAttribute('lang'),
       languageHeader: true,
diff --git a/packages/ajax/src/ajax.js b/packages/ajax/src/ajax.js
index 4ce5f5e39..540f690c5 100644
--- a/packages/ajax/src/ajax.js
+++ b/packages/ajax/src/ajax.js
@@ -4,7 +4,7 @@ import { AjaxClass } from './AjaxClass.js';
 /**
  * @typedef {ajax} ajax the global instance for handling all ajax requests
  */
-export let ajax = singletonManager.get('@lion/ajax::ajax::0.3.x') || AjaxClass.getInstance(); // eslint-disable-line import/no-mutable-exports
+export let ajax = singletonManager.get('@lion/ajax::ajax::0.3.x') || new AjaxClass(); // eslint-disable-line import/no-mutable-exports
 
 /**
  * setAjax allows the Application Developer to override the globally used instance of {@link:ajax}.
diff --git a/packages/ajax/test/AjaxClass.interceptors.test.js b/packages/ajax/test/AjaxClass.interceptors.test.js
index 3c1f6f389..18c0c9442 100644
--- a/packages/ajax/test/AjaxClass.interceptors.test.js
+++ b/packages/ajax/test/AjaxClass.interceptors.test.js
@@ -6,6 +6,10 @@ import { AjaxClass } from '../src/AjaxClass.js';
 describe('AjaxClass interceptors', () => {
   let server;
 
+  function getInstance(cfg) {
+    return new AjaxClass(cfg);
+  }
+
   beforeEach(() => {
     server = sinon.fakeServer.create({ autoRespond: true });
   });
@@ -24,8 +28,8 @@ describe('AjaxClass interceptors', () => {
             this[type] = [...this[type], myInterceptor];
           }
         }
-        const ajaxWithout = AjaxClass.getNewInstance();
-        const ajaxWith = MyApi.getNewInstance();
+        const ajaxWithout = getInstance();
+        const ajaxWith = new MyApi();
         expect(ajaxWithout[type]).to.not.include(myInterceptor);
         expect(ajaxWith[type]).to.include(myInterceptor);
       });
@@ -34,8 +38,8 @@ describe('AjaxClass interceptors', () => {
     it('can be added per instance without changing the class', () => {
       ['requestInterceptors', 'responseInterceptors'].forEach(type => {
         const myInterceptor = () => {};
-        const ajaxWithout = AjaxClass.getNewInstance();
-        const ajaxWith = AjaxClass.getNewInstance();
+        const ajaxWithout = getInstance();
+        const ajaxWith = getInstance();
         ajaxWith[type].push(myInterceptor);
         expect(ajaxWithout[type]).to.not.include(myInterceptor);
         expect(ajaxWith[type]).to.include(myInterceptor);
@@ -53,7 +57,7 @@ describe('AjaxClass interceptors', () => {
 
           const myInterceptor = sinon.spy(foo => foo);
 
-          const ajax = AjaxClass.getNewInstance();
+          const ajax = getInstance();
 
           ajax[type].push(myInterceptor);
           await ajax.get('data.json');
@@ -68,7 +72,7 @@ describe('AjaxClass interceptors', () => {
 
     it('has access to provided instance config(options) on requestInterceptors', async () => {
       server.respondWith('GET', 'data.json', [200, { 'Content-Type': 'application/json' }, '{}']);
-      const ajax = AjaxClass.getNewInstance();
+      const ajax = getInstance();
       ajax.options.myCustomValue = 'foo';
       let customValueAccess = false;
       const myInterceptor = config => {
@@ -94,7 +98,7 @@ describe('AjaxClass interceptors', () => {
         '{ "method": "put" }',
       ]);
       const enforcePutInterceptor = config => ({ ...config, method: 'PUT' });
-      const myAjax = AjaxClass.getNewInstance();
+      const myAjax = getInstance();
       myAjax.requestInterceptors.push(enforcePutInterceptor);
       const response = await myAjax.post('data.json');
       expect(response.data).to.deep.equal({ method: 'put' });
@@ -112,7 +116,7 @@ describe('AjaxClass interceptors', () => {
         ...response,
         data: { ...response.data, foo: 'bar' },
       });
-      const myAjax = AjaxClass.getNewInstance();
+      const myAjax = getInstance();
       myAjax.responseInterceptors.push(addDataInterceptor);
       const response = await myAjax.get('data.json');
       expect(response.data).to.deep.equal({ method: 'get', foo: 'bar' });
diff --git a/packages/ajax/test/AjaxClass.test.js b/packages/ajax/test/AjaxClass.test.js
index 04b59711f..5738d9dd2 100644
--- a/packages/ajax/test/AjaxClass.test.js
+++ b/packages/ajax/test/AjaxClass.test.js
@@ -7,6 +7,10 @@ import { ajax } from '../src/ajax.js';
 describe('AjaxClass', () => {
   let server;
 
+  function getInstance(cfg) {
+    return new AjaxClass(cfg);
+  }
+
   beforeEach(() => {
     server = sinon.fakeServer.create({ autoRespond: true });
   });
@@ -16,16 +20,16 @@ describe('AjaxClass', () => {
   });
 
   it('sets content type json if passed an object', async () => {
-    const myAjax = AjaxClass.getNewInstance();
+    const myAjax = getInstance();
     server.respondWith('POST', /\/api\/foo/, [200, { 'Content-Type': 'application/json' }, '']);
     await myAjax.post('/api/foo', { a: 1, b: 2 });
     expect(server.requests[0].requestHeaders['Content-Type']).to.include('application/json');
   });
 
-  describe('AjaxClass.getNewInstance({ jsonPrefix: "%prefix%" })', () => {
+  describe('AjaxClass({ jsonPrefix: "%prefix%" })', () => {
     it('adds new transformer to responseDataTransformers', () => {
-      const myAjaxWithout = AjaxClass.getNewInstance({ jsonPrefix: '' });
-      const myAjaxWith = AjaxClass.getNewInstance({ jsonPrefix: 'prefix' });
+      const myAjaxWithout = getInstance({ jsonPrefix: '' });
+      const myAjaxWith = getInstance({ jsonPrefix: 'prefix' });
       const lengthWithout = myAjaxWithout.responseDataTransformers.length;
       const lengthWith = myAjaxWith.responseDataTransformers.length;
       expect(lengthWith - lengthWithout).to.eql(1);
@@ -38,7 +42,7 @@ describe('AjaxClass', () => {
         'for(;;);{"success":true}',
       ]);
 
-      const myAjax = AjaxClass.getNewInstance({ jsonPrefix: 'for(;;);' });
+      const myAjax = getInstance({ jsonPrefix: 'for(;;);' });
       const response = await myAjax.get('data.json');
       expect(response.status).to.equal(200);
       expect(response.data.success).to.equal(true);
@@ -47,24 +51,24 @@ describe('AjaxClass', () => {
     it('works with non-JSON responses', async () => {
       server.respondWith('GET', 'data.txt', [200, { 'Content-Type': 'text/plain' }, 'some text']);
 
-      const myAjax = AjaxClass.getNewInstance({ jsonPrefix: 'for(;;);' });
+      const myAjax = getInstance({ jsonPrefix: 'for(;;);' });
       const response = await myAjax.get('data.txt');
       expect(response.status).to.equal(200);
       expect(response.data).to.equal('some text');
     });
   });
 
-  describe('AjaxClass.getNewInstance({ cancelable: true })', () => {
+  describe('AjaxClass({ cancelable: true })', () => {
     it('adds new interceptor to requestInterceptors', () => {
-      const myAjaxWithout = AjaxClass.getNewInstance();
-      const myAjaxWith = AjaxClass.getNewInstance({ cancelable: true });
+      const myAjaxWithout = getInstance();
+      const myAjaxWith = getInstance({ cancelable: true });
       const lengthWithout = myAjaxWithout.requestInterceptors.length;
       const lengthWith = myAjaxWith.requestInterceptors.length;
       expect(lengthWith - lengthWithout).to.eql(1);
     });
 
     it('allows to cancel single running requests', async () => {
-      const myAjax = AjaxClass.getNewInstance({ cancelable: true });
+      const myAjax = getInstance({ cancelable: true });
 
       setTimeout(() => {
         myAjax.cancel('is cancelled');
@@ -79,7 +83,7 @@ describe('AjaxClass', () => {
     });
 
     it('allows to cancel multiple running requests', async () => {
-      const myAjax = AjaxClass.getNewInstance({ cancelable: true });
+      const myAjax = getInstance({ cancelable: true });
       let cancelCount = 0;
 
       setTimeout(() => {
@@ -102,7 +106,7 @@ describe('AjaxClass', () => {
     });
 
     it('does not cancel resolved requests', async () => {
-      const myAjax = AjaxClass.getNewInstance({ cancelable: true });
+      const myAjax = getInstance({ cancelable: true });
       server.respondWith('GET', 'data.json', [
         200,
         { 'Content-Type': 'application/json' },
@@ -119,17 +123,17 @@ describe('AjaxClass', () => {
     });
   });
 
-  describe('AjaxClass.getNewInstance({ cancelPreviousOnNewRequest: true })', () => {
+  describe('AjaxClass({ cancelPreviousOnNewRequest: true })', () => {
     it('adds new interceptor to requestInterceptors', () => {
-      const myAjaxWithout = AjaxClass.getNewInstance();
-      const myAjaxWith = AjaxClass.getNewInstance({ cancelPreviousOnNewRequest: true });
+      const myAjaxWithout = getInstance();
+      const myAjaxWith = getInstance({ cancelPreviousOnNewRequest: true });
       const lengthWithout = myAjaxWithout.requestInterceptors.length;
       const lengthWith = myAjaxWith.requestInterceptors.length;
       expect(lengthWith - lengthWithout).to.eql(1);
     });
 
     it('automatically cancels previous running request', async () => {
-      const myAjax = AjaxClass.getNewInstance({ cancelPreviousOnNewRequest: true });
+      const myAjax = getInstance({ cancelPreviousOnNewRequest: true });
       server.respondWith('GET', 'data.json', [
         200,
         { 'Content-Type': 'application/json' },
@@ -157,7 +161,7 @@ describe('AjaxClass', () => {
     });
 
     it('automatically cancels multiple previous requests to the same endpoint', async () => {
-      const myAjax = AjaxClass.getNewInstance({ cancelPreviousOnNewRequest: true });
+      const myAjax = getInstance({ cancelPreviousOnNewRequest: true });
       server.respondWith('GET', 'data.json', [
         200,
         { 'Content-Type': 'application/json' },
@@ -189,7 +193,7 @@ describe('AjaxClass', () => {
     });
 
     it('automatically cancels multiple previous requests to different endpoints', async () => {
-      const myAjax = AjaxClass.getNewInstance({ cancelPreviousOnNewRequest: true });
+      const myAjax = getInstance({ cancelPreviousOnNewRequest: true });
       server.respondWith('GET', 'data.json', [
         200,
         { 'Content-Type': 'application/json' },
@@ -221,7 +225,7 @@ describe('AjaxClass', () => {
     });
 
     it('does not automatically cancel requests made via generic ajax', async () => {
-      const myAjax = AjaxClass.getNewInstance({ cancelPreviousOnNewRequest: true });
+      const myAjax = getInstance({ cancelPreviousOnNewRequest: true });
       server.respondWith('GET', 'data.json', [
         200,
         { 'Content-Type': 'application/json' },
@@ -257,8 +261,8 @@ describe('AjaxClass', () => {
     });
 
     it('does not automatically cancel requests made via other instances', async () => {
-      const myAjax1 = AjaxClass.getNewInstance({ cancelPreviousOnNewRequest: true });
-      const myAjax2 = AjaxClass.getNewInstance({ cancelPreviousOnNewRequest: true });
+      const myAjax1 = getInstance({ cancelPreviousOnNewRequest: true });
+      const myAjax2 = getInstance({ cancelPreviousOnNewRequest: true });
       server.respondWith('GET', 'data.json', [
         200,
         { 'Content-Type': 'application/json' },
diff --git a/packages/ajax/test/AjaxClass.transformers.test.js b/packages/ajax/test/AjaxClass.transformers.test.js
index 1a7344182..847e9f42c 100644
--- a/packages/ajax/test/AjaxClass.transformers.test.js
+++ b/packages/ajax/test/AjaxClass.transformers.test.js
@@ -6,6 +6,10 @@ import { AjaxClass } from '../src/AjaxClass.js';
 describe('AjaxClass transformers', () => {
   let server;
 
+  function getInstance(cfg) {
+    return new AjaxClass(cfg);
+  }
+
   beforeEach(() => {
     server = sinon.fakeServer.create({ autoRespond: true });
   });
@@ -24,18 +28,18 @@ describe('AjaxClass transformers', () => {
             this[type] = [...this[type], myInterceptor];
           }
         }
-        const ajaxWithout = AjaxClass.getNewInstance();
-        const ajaxWith = MyApi.getNewInstance();
+        const ajaxWithout = getInstance();
+        const ajaxWith = new MyApi();
         expect(ajaxWithout[type]).to.not.include(myInterceptor);
         expect(ajaxWith[type]).to.include(myInterceptor);
       });
     });
 
-    it('can be added per instance withour changing the class', () => {
+    it('can be added per instance without changing the class', () => {
       ['requestDataTransformers', 'responseDataTransformers'].forEach(type => {
         const myInterceptor = () => {};
-        const ajaxWithout = AjaxClass.getNewInstance();
-        const ajaxWith = AjaxClass.getNewInstance();
+        const ajaxWithout = getInstance();
+        const ajaxWith = getInstance();
         ajaxWith[type].push(myInterceptor);
         expect(ajaxWithout[type]).to.not.include(myInterceptor);
         expect(ajaxWith[type]).to.include(myInterceptor);
@@ -53,7 +57,7 @@ describe('AjaxClass transformers', () => {
 
           const myTransformer = sinon.spy(foo => foo);
 
-          const ajax = AjaxClass.getNewInstance();
+          const ajax = getInstance();
 
           ajax[type].push(myTransformer);
           await ajax.get('data.json');
@@ -75,7 +79,7 @@ describe('AjaxClass transformers', () => {
         '{ "method": "post" }',
       ]);
       const addBarTransformer = data => ({ ...data, bar: 'bar' });
-      const myAjax = AjaxClass.getNewInstance();
+      const myAjax = getInstance();
       myAjax.requestDataTransformers.push(addBarTransformer);
       const response = await myAjax.post('data.json', { foo: 'foo' });
       expect(JSON.parse(response.config.data)).to.deep.equal({
@@ -93,7 +97,7 @@ describe('AjaxClass transformers', () => {
         '{ "method": "get" }',
       ]);
       const addBarTransformer = data => ({ ...data, bar: 'bar' });
-      const myAjax = AjaxClass.getNewInstance();
+      const myAjax = getInstance();
       myAjax.responseDataTransformers.push(addBarTransformer);
       const response = await myAjax.get('data.json');
       expect(response.data).to.deep.equal({ method: 'get', bar: 'bar' });
diff --git a/packages/core/index.js b/packages/core/index.js
index 5b06d917f..3e3c95088 100644
--- a/packages/core/index.js
+++ b/packages/core/index.js
@@ -53,7 +53,6 @@ export { dedupeMixin } from '@open-wc/dedupe-mixin';
 export { DelegateMixin } from './src/DelegateMixin.js';
 export { DisabledMixin } from './src/DisabledMixin.js';
 export { DisabledWithTabIndexMixin } from './src/DisabledWithTabIndexMixin.js';
-export { LionSingleton } from './src/LionSingleton.js';
 export { SlotMixin } from './src/SlotMixin.js';
 export { UpdateStylesMixin } from './src/UpdateStylesMixin.js';
 export { browserDetection } from './src/browserDetection.js';
diff --git a/packages/core/src/LionSingleton.js b/packages/core/src/LionSingleton.js
deleted file mode 100644
index de864ab3f..000000000
--- a/packages/core/src/LionSingleton.js
+++ /dev/null
@@ -1,51 +0,0 @@
-/**
- * 'LionSingleton' provides an instance of the given class via .getInstance(foo, bar) and will
- * return the same instance if already created. It can reset its instance so a new one will be
- * created via .resetInstance() and can at any time add mixins via .addInstanceMixin().
- * It can provide new instances (with applied Mixins) via .getNewInstance().
- */
-export class LionSingleton {
-  /**
-   * @param {function} mixin
-   */
-  static addInstanceMixin(mixin) {
-    if (!this.__instanceMixins) {
-      /** @type {function[]} */
-      this.__instanceMixins = [];
-    }
-    this.__instanceMixins.push(mixin);
-  }
-
-  /**
-   * @param {...*} args
-   * @returns {LionSingleton}
-   */
-  static getNewInstance(...args) {
-    let Klass = this;
-    if (Array.isArray(this.__instanceMixins)) {
-      this.__instanceMixins.forEach(mixin => {
-        Klass = mixin(Klass);
-      });
-    }
-    // Ignoring, because it's up to the extension layer to accept arguments in its constructor
-    // @ts-ignore-next-line
-    return new Klass(...args);
-  }
-
-  /**
-   * @param {...*} args
-   * @returns {*}
-   */
-  static getInstance(...args) {
-    if (this.__instance) {
-      return this.__instance;
-    }
-
-    this.__instance = this.getNewInstance(...args);
-    return this.__instance;
-  }
-
-  static resetInstance() {
-    this.__instance = undefined;
-  }
-}
diff --git a/packages/core/test/LionSingleton.test.js b/packages/core/test/LionSingleton.test.js
deleted file mode 100644
index 27d808294..000000000
--- a/packages/core/test/LionSingleton.test.js
+++ /dev/null
@@ -1,126 +0,0 @@
-import { expect } from '@open-wc/testing';
-
-import { LionSingleton } from '../src/LionSingleton.js';
-
-describe('LionSingleton', () => {
-  it('provides an instance of the given class via .getInstance()', async () => {
-    class MySingleton extends LionSingleton {}
-    const mySingleton = MySingleton.getInstance();
-    expect(mySingleton).to.be.an.instanceOf(MySingleton);
-  });
-
-  it('supports parameters for .getInstance(foo, bar)', async () => {
-    class MySingleton extends LionSingleton {
-      /**
-       *
-       * @param {string} foo
-       * @param {string} bar
-       */
-      constructor(foo, bar) {
-        super();
-        this.foo = foo;
-        this.bar = bar;
-      }
-    }
-    const mySingleton = MySingleton.getInstance('isFoo', 'isBar');
-    expect(mySingleton).to.deep.equal({
-      foo: 'isFoo',
-      bar: 'isBar',
-    });
-  });
-
-  it('will return the same instance if already created', async () => {
-    let counter = 0;
-    class MySingleton extends LionSingleton {
-      constructor() {
-        super();
-        counter += 1;
-      }
-    }
-    const mySingleton = MySingleton.getInstance();
-    mySingleton.foo = 'bar';
-    expect(mySingleton).to.deep.equal(MySingleton.getInstance());
-    expect(counter).to.equal(1);
-    expect(new MySingleton()).to.not.deep.equal(MySingleton.getInstance());
-  });
-
-  it('can reset its instance so a new one will be created via .resetInstance()', async () => {
-    let counter = 0;
-    class MySingleton extends LionSingleton {
-      constructor() {
-        super();
-        counter += 1;
-      }
-    }
-    const mySingleton = MySingleton.getInstance();
-    mySingleton.foo = 'bar';
-    expect(mySingleton.foo).to.equal('bar');
-    expect(counter).to.equal(1);
-
-    MySingleton.resetInstance();
-    const updatedSingleton = MySingleton.getInstance();
-    expect(updatedSingleton.foo).to.be.undefined;
-    expect(counter).to.equal(2);
-  });
-
-  it('can at any time add mixins via .addInstanceMixin()', () => {
-    // @ts-ignore because we're getting rid of LionSingleton altogether
-    const MyMixin = superclass =>
-      class extends superclass {
-        constructor() {
-          super();
-          this.myMixin = true;
-        }
-      };
-    class MySingleton extends LionSingleton {}
-
-    MySingleton.addInstanceMixin(MyMixin);
-    const mySingleton = MySingleton.getInstance();
-    expect(mySingleton.myMixin).to.be.true;
-
-    // @ts-ignore because we're getting rid of LionSingleton altogether
-    const OtherMixin = superclass =>
-      class extends superclass {
-        constructor() {
-          super();
-          this.otherMixin = true;
-        }
-      };
-    MySingleton.addInstanceMixin(OtherMixin);
-    expect(mySingleton.otherMixin).to.be.undefined;
-
-    MySingleton.resetInstance();
-    const updatedSingleton = MySingleton.getInstance();
-    expect(updatedSingleton.myMixin).to.be.true;
-    expect(updatedSingleton.otherMixin).to.be.true;
-  });
-
-  it('can provide new instances (with applied Mixins) via .getNewInstance()', async () => {
-    // @ts-ignore because we're getting rid of LionSingleton altogether
-    const MyMixin = superclass =>
-      class extends superclass {
-        constructor() {
-          super();
-          this.myMixin = true;
-        }
-      };
-    class MySingleton extends LionSingleton {}
-
-    MySingleton.addInstanceMixin(MyMixin);
-    const singletonOne = MySingleton.getNewInstance();
-    // @ts-ignore because we're getting rid of LionSingleton altogether
-    singletonOne.one = true;
-    // @ts-ignore because we're getting rid of LionSingleton altogether
-    expect(singletonOne.myMixin).to.be.true;
-    // @ts-ignore because we're getting rid of LionSingleton altogether
-    expect(singletonOne.one).to.be.true;
-
-    const singletonTwo = MySingleton.getNewInstance();
-    // @ts-ignore because we're getting rid of LionSingleton altogether
-    expect(singletonTwo.myMixin).to.be.true;
-    // @ts-ignore because we're getting rid of LionSingleton altogether
-    expect(singletonTwo.one).to.be.undefined;
-    // @ts-ignore because we're getting rid of LionSingleton altogether
-    expect(singletonOne.one).to.be.true; // to be sure
-  });
-});
diff --git a/packages/icon/src/IconManager.js b/packages/icon/src/IconManager.js
index fefd7c142..b3413c04c 100644
--- a/packages/icon/src/IconManager.js
+++ b/packages/icon/src/IconManager.js
@@ -1,9 +1,5 @@
-import { LionSingleton } from '@lion/core';
-
-export class IconManager extends LionSingleton {
-  constructor(params = {}) {
-    super(params);
-
+export class IconManager {
+  constructor() {
     this.__iconResolvers = new Map();
   }
 
diff --git a/packages/icon/src/icons.js b/packages/icon/src/icons.js
index f9d3e2f54..c1b42554e 100644
--- a/packages/icon/src/icons.js
+++ b/packages/icon/src/icons.js
@@ -2,7 +2,7 @@ import { singletonManager } from 'singleton-manager';
 import { IconManager } from './IconManager.js';
 
 // eslint-disable-next-line import/no-mutable-exports
-export let icons = singletonManager.get('@lion/icon::icons::0.5.x') || IconManager.getInstance();
+export let icons = singletonManager.get('@lion/icon::icons::0.5.x') || new IconManager();
 
 export function setIcons(newIcons) {
   icons = newIcons;
diff --git a/packages/localize/src/LocalizeManager.js b/packages/localize/src/LocalizeManager.js
index faa9840a6..d6eaf03fd 100644
--- a/packages/localize/src/LocalizeManager.js
+++ b/packages/localize/src/LocalizeManager.js
@@ -1,5 +1,4 @@
 import MessageFormat from '@bundled-es-modules/message-format/MessageFormat.js';
-import { LionSingleton } from '@lion/core';
 import isLocalizeESModule from './isLocalizeESModule.js';
 
 /**
@@ -9,10 +8,9 @@ import isLocalizeESModule from './isLocalizeESModule.js';
 /**
  * `LocalizeManager` manages your translations (includes loading)
  */
-export class LocalizeManager extends LionSingleton {
+export class LocalizeManager {
   // eslint-disable-line no-unused-vars
   constructor({ autoLoadOnLocaleChange = false, fallbackLocale = '' } = {}) {
-    super();
     this.__delegationTarget = document.createDocumentFragment();
     this._autoLoadOnLocaleChange = !!autoLoadOnLocaleChange;
     this._fallbackLocale = fallbackLocale;
diff --git a/packages/localize/src/localize.js b/packages/localize/src/localize.js
index ead5dac76..ba8e522a6 100644
--- a/packages/localize/src/localize.js
+++ b/packages/localize/src/localize.js
@@ -5,7 +5,7 @@ import { LocalizeManager } from './LocalizeManager.js';
 // eslint-disable-next-line import/no-mutable-exports
 export let localize =
   singletonManager.get('@lion/localize::localize::0.10.x') ||
-  LocalizeManager.getInstance({
+  new LocalizeManager({
     autoLoadOnLocaleChange: true,
     fallbackLocale: 'en-GB',
   });
diff --git a/packages/localize/test/LocalizeManager.test.js b/packages/localize/test/LocalizeManager.test.js
index 3b9b6543f..237c90253 100644
--- a/packages/localize/test/LocalizeManager.test.js
+++ b/packages/localize/test/LocalizeManager.test.js
@@ -643,8 +643,7 @@ describe('When supporting external translation tools like Google Translate', ()
    *  @returns {LocalizeManager}
    */
   function getInstance(cfg) {
-    LocalizeManager.resetInstance();
-    return LocalizeManager.getInstance(cfg || {});
+    return new LocalizeManager(cfg || {});
   }
 
   afterEach(() => {
diff --git a/packages/localize/test/localize.test.js b/packages/localize/test/localize.test.js
index f7ea31c6c..a15cdcdc8 100644
--- a/packages/localize/test/localize.test.js
+++ b/packages/localize/test/localize.test.js
@@ -1,7 +1,5 @@
 import { expect } from '@open-wc/testing';
 import sinon from 'sinon';
-
-import { LionSingleton } from '@lion/core';
 import { LocalizeManager } from '../src/LocalizeManager.js';
 
 import { localize, setLocalize } from '../src/localize.js';
@@ -13,10 +11,6 @@ describe('localize', () => {
   // we test newly created instances of this class separately
   // this allows to avoid any side effects caused by changing singleton state between tests
 
-  it('is a singleton', () => {
-    expect(localize).to.be.an.instanceOf(LionSingleton);
-  });
-
   it('is an instance of LocalizeManager', () => {
     expect(localize).to.be.an.instanceOf(LocalizeManager);
   });