fix(chartist.component): throw error if chart does not have data or type

Closes #41

Signed-off-by: Will Soto <[email protected]>

src/chartist.component.ts

@@ -49,6 +49,10 @@ class ChartistComponent implements OnInit, OnChanges, OnDestroy {
   }
 
   ngOnInit(): Promise<ChartInterfaces> {
+    if (!this.type || !this.data) {
+      Promise.reject(`Expected at least type and data. Got ${this.type} for type and ${this.data} for data`);
+    }
+
     return this.renderChart().then((chart) => {
       if (this.events !== undefined) {
         this.bindEvents(chart);

test/chartist.component.spec.ts

@@ -147,4 +147,22 @@ describe('chartist component', function(): void {
       expect(instance.chart.update).toHaveBeenCalled();
     });
   }));
+
+  it('should throw an error when missing type', async(() => {
+    let fixture = TestBed.createComponent(ChartistComponent);
+    let instance: ChartistComponent = fixture.debugElement.componentInstance;
+
+    instance.data = data['Bar'];
+
+    expect(instance.ngOnInit).toThrow();
+  }));
+
+  it('should throw an error when missing data', async(() => {
+    let fixture = TestBed.createComponent(ChartistComponent);
+    let instance: ChartistComponent = fixture.debugElement.componentInstance;
+
+    instance.type = 'Bar';
+
+    expect(instance.ngOnInit).toThrow();
+  }));
 });