docs(#1244): fix buttons example for excel export

Author: l-lin

demo/angular.json

@@ -34,6 +34,7 @@
             "scripts": [
               "node_modules/jquery/dist/jquery.js",
               "node_modules/tether/dist/js/tether.js",
+              "node_modules/jszip/dist/jszip.js",
               "node_modules/datatables.net/js/jquery.dataTables.js",
               "node_modules/datatables.net-buttons/js/dataTables.buttons.js",
               "node_modules/datatables.net-buttons/js/buttons.colVis.js",
@@ -93,6 +94,7 @@
               "node_modules/jquery/dist/jquery.js",
               "node_modules/tether/dist/js/tether.js",
               "node_modules/datatables.net/js/jquery.dataTables.js",
+              "node_modules/jszip/dist/jszip.js",
               "node_modules/datatables.net-buttons/js/dataTables.buttons.js",
               "node_modules/datatables.net-buttons/js/buttons.colVis.js",
               "node_modules/datatables.net-buttons/js/buttons.flash.js",
@@ -169,4 +171,4 @@
       "prefix": "app"
     }
   }
-}
+}

demo/package.json

@@ -37,6 +37,7 @@
     "datatables.net-select-dt": "^1.2.3",
     "highlight.js": "^9.12.0",
     "jquery": "^3.2.1",
+    "jszip": "^3.1.5",
     "materialize-css": "0.100.2",
     "rxjs": "^6.1.0",
     "rxjs-compat": "^6.1.0",

demo/src/app/extensions/buttons-extension-configuration.component.ts

@@ -15,13 +15,16 @@ import { Component } from '@angular/core';
   <h4 id="angular-cli">.angular-cli.json</h4>
   <p>Add the dependencies in the scripts and styles attributes:</p>
   <section [innerHTML]="angularCliJsonSnippet" highlight-js-content=".json"></section>
+  <blockquote>If you want to have the excel export functionnality, then you must import the <code>jszip.js</code> before the <code>buttons.html5.js</code> file.</blockquote>
 </div>
   `
 })
 export class ButtonsExtensionConfigurationComponent {
   npmInstallSnippet = `
 <pre>
-<code class="bash highlight"># JS file
+<code class="bash highlight"># If you want to export excel files
+npm install jszip --save
+# JS file
 npm install datatables.net-buttons --save
 # CSS file
 npm install datatables.net-buttons-dt --save
@@ -41,6 +44,7 @@ npm install @types/datatables.net-buttons --save-dev
       ],
       "scripts": [
         ...
+        "../node_modules/jszip/dist/jszip.js",
         "../node_modules/datatables.net-buttons/js/dataTables.buttons.js",
         "../node_modules/datatables.net-buttons/js/buttons.colVis.js",
         "../node_modules/datatables.net-buttons/js/buttons.flash.js",