feat: add elementTemplates#getIncompatibleEngines API

Can be used to test an element template for compatibility,
returning current and expected engine versions.

src/element-templates/ElementTemplates.js

@@ -196,24 +196,35 @@ export default class ElementTemplates {
    * @return {boolean} - true if compatible or no engine is set for elementTemplates or template.
    */
   isCompatible(template) {
+    return !Object.keys(this.getIncompatibleEngines(template)).length;
+  }
+
+  /**
+   * Get engines that are incompatible with the template.
+   *
+   * @param {any} template
+   *
+   * @return { Record<string, { required: string, found: string } } - incompatible engines along with their template and local versions
+   */
+  getIncompatibleEngines(template) {
     const localEngines = this._engines;
     const templateEngines = template.engines;
 
-    for (const engine in templateEngines) {
-
-      // we check compatibility against all locally provided
-      // engines, hence computing the overlap here.
+    return reduce(templateEngines, (result, _, engine) => {
 
       if (!has(localEngines, engine)) {
-        continue;
+        return result;
       }
 
       if (!isSemverCompatible(localEngines[engine], templateEngines[engine])) {
-        return false;
+        result[engine] = {
+          actual: localEngines[engine],
+          required: templateEngines[engine]
+        };
       }
-    }
 
-    return true;
+      return result;
+    }, {});
   }
 
   /**

test/spec/cloud-element-templates/ElementTemplates.spec.js

@@ -1491,6 +1491,86 @@ describe('provider/cloud-element-templates - ElementTemplates', function() {
     }));
   });
 
+
+  describe('getIncompatibleEngines', function() {
+
+    it('should return incompatible engine', inject(function(elementTemplates) {
+
+      // given
+      elementTemplates.setEngines({
+        camunda: '8.5'
+      });
+
+      const template = {
+        engines: {
+          camunda: '>= 8.6'
+        }
+      };
+
+      // then
+      const result = elementTemplates.getIncompatibleEngines(template);
+
+      expect(result).to.eql({
+        camunda: {
+          actual: '8.5.0',
+          required: '>= 8.6'
+        }
+      });
+    }));
+
+
+    it('should return multiple', inject(function(elementTemplates) {
+
+      // given
+      elementTemplates.setEngines({
+        camunda: '8.5',
+        desktopModeler: '5.30'
+      });
+
+      const template = {
+        engines: {
+          camunda: '>= 8.6',
+          desktopModeler: '^4.0'
+        }
+      };
+
+      // then
+      const result = elementTemplates.getIncompatibleEngines(template);
+
+      expect(result).to.eql({
+        camunda: {
+          actual: '8.5.0',
+          required: '>= 8.6'
+        },
+        desktopModeler: {
+          actual: '5.30.0',
+          required: '^4.0'
+        }
+      });
+    }));
+
+
+    it('should return empty object if compatible', inject(function(elementTemplates) {
+
+      // given
+      elementTemplates.setEngines({
+        nonMatchingEngine: '8.5'
+      });
+
+      const template = {
+        engines: {
+          camunda: '8.5',
+        }
+      };
+
+      // then
+      const result = elementTemplates.getIncompatibleEngines(template);
+
+      expect(result).to.eql({});
+    }));
+
+  });
+
 });
 
 
@@ -1531,6 +1611,8 @@ describe('provider/cloud-element-templates - ElementTemplates - error handling o
 });
 
 
+
+
 describe('provider/cloud-element-templates - ElementTemplates - integration', function() {
 
   let container;