refactoring model singleton logic

Author: perki

package.json

@@ -1,6 +1,6 @@
 {
   "name": "hds-lib",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "description": "Health Data Safe - Library",
   "main": "src/index.js",
   "scripts": {

src/HDSModel/HDSModel.js

@@ -38,10 +38,17 @@ class HDSModel {
     this.laziliyLoadedMap = { };
   }
 
+  get isLoaded () {
+    return !!this.#modelData;
+  }
+
   /**
    * Load model definitions
    */
-  async load () {
+  async load (modelUrl = null) {
+    if (modelUrl) {
+      this.#modelUrl = modelUrl;
+    }
     const response = await fetch(this.#modelUrl);
     const resultText = await response.text();
     const result = JSON.parse(resultText);
@@ -56,7 +63,7 @@ class HDSModel {
 
   /** RAW model data */
   get modelData () {
-    if (!this.#modelData) throw new Error('Model not loaded call `await model.load()` first.');
+    if (!this.isLoaded) throw new Error('Model not loaded call `HDSLib.initHDSModel()` or `await model.load()` first.');
     return this.#modelData;
   }
 }
@@ -65,6 +72,7 @@ class HDSModel {
 for (const [prop, Obj] of Object.entries(LAZILY_LOADED)) {
   Object.defineProperty(HDSModel.prototype, prop, {
     get: function () {
+      if (!this.isLoaded) throw new Error('Model not loaded call `HDSLib.initHDSModel()` or `await model.load()` first.');
       if (!this.laziliyLoadedMap[prop]) this.laziliyLoadedMap[prop] = new Obj(this);
       return this.laziliyLoadedMap[prop];
     }

src/HDSModel/HDSModelInitAndSingleton.js

@@ -1,28 +1,31 @@
 let model = null;
 const HDSModel = require('./HDSModel');
 const HDService = require('../HDSService');
-const { HDSLibError } = require('../errors');
 
 module.exports = {
   getModel,
   initHDSModel
 };
 
 function getModel () {
-  if (model == null) throw new HDSLibError('Call await HDSLib.initHDSModel() once');
+  if (model == null) {
+    model = new HDSModel();
+  }
   return model;
 }
 
 /**
  * Initialized model singleton
  * @returns {HDSModel}
  */
-async function initHDSModel (forceNew = false) {
-  if (!model || forceNew) {
+async function initHDSModel () {
+  if (!model) {
+    getModel();
+  }
+  if (!model.isLoaded) {
     const service = new HDService();
     const serviceInfo = await service.info();
-    model = new HDSModel(serviceInfo.assets['hds-model']);
-    await model.load();
+    await model.load(serviceInfo.assets['hds-model']);
   }
   return model;
 }

tests/hdsLib.test.js

@@ -10,14 +10,22 @@ describe('[HDLX] HDSLib.index.js', () => {
   it('[HDME] HDSLib.model throws error if not initialized', () => {
     try {
       // eslint-disable-next-line no-unused-expressions
-      HDSLib.model;
+      HDSLib.model.modelData;
       throw new Error('Should throw an error');
     } catch (e) {
-      assert.equal(e.message, 'Call await HDSLib.initHDSModel() once');
+      assert.equal(e.message, 'Model not loaded call `HDSLib.initHDSModel()` or `await model.load()` first.');
+    }
+
+    try {
+      // eslint-disable-next-line no-unused-expressions
+      HDSLib.model.streams;
+      throw new Error('Should throw an error');
+    } catch (e) {
+      assert.equal(e.message, 'Model not loaded call `HDSLib.initHDSModel()` or `await model.load()` first.');
     }
   });
 
-  it('[HDME] HDSLib.initHDSModel()', async () => {
+  it('[HDMF] HDSLib.initHDSModel()', async () => {
     const model0 = await HDSLib.initHDSModel();
     const model1 = await HDSLib.initHDSModel();
     assert.equal(model0, model1, 'HDSLib.initHDSModel() should used cached model');
@@ -26,14 +34,6 @@ describe('[HDLX] HDSLib.index.js', () => {
     // -- refresh model
   });
 
-  it('[HDME] HDSLib.initHDSModel(forceRefresh = true) should refresh model', async () => {
-    const model0 = await HDSLib.initHDSModel();
-    const model1 = await HDSLib.initHDSModel(true);
-    assert.ok(model0 !== model1, 'HDSLib.initHDSModel(true) should refresh cached model');
-    const model2 = HDSLib.model;
-    assert.equal(model1, model2, 'HDSLib.model should used cached model');
-  });
-
   describe('[HDUX] Utils', () => {
     it('[HDUW] utils.waitUntilFalse', async function () {
       this.timeout('1000');