fix: Fix typescript issue #614 (#621)

package.json

@@ -63,6 +63,9 @@
   "peerDependencies": {
     "chart.js": ">= 2.5"
   },
+  "dependencies": {
+    "@types/chart.js": "^2.7.55"
+  },
   "devDependencies": {
     "@babel/cli": "^7.0.0-beta.42",
     "@babel/core": "^7.0.0-beta.42",

types/components.d.ts

@@ -1,8 +1,8 @@
 import Vue from 'vue'
-import { ChartData, ChartOptions } from 'chart.js';
+import 'chart.js'
 
 /** vue-chartjs component common definition */
 export declare class BaseChart extends Vue {
   addPlugin (plugin?: object): void
-  renderChart (chartData: ChartData, options?: ChartOptions): void
+  renderChart (chartData: Chart.ChartData, options?: Chart.ChartOptions): void
 }

types/mixins.d.ts

@@ -1,10 +1,10 @@
 import Vue from 'vue';
-import { ChartData } from 'chart.js';
+import 'chart.js';
 
 export declare class ReactiveDataMixin extends Vue {
-  chartData: ChartData;
+  chartData: Chart.ChartData;
 }
 
 export declare class ReactivePropMixin extends Vue {
-  readonly chartData: ChartData;
+  readonly chartData: Chart.ChartData;
 }