fix/issue-395/globalAlert (#403)

* Add cookie functionality, update examples in blank

src/components/global-alert/_global-alert.hbs

@@ -1,4 +1,4 @@
-<div class="nsw-global-alert{{#if type}} nsw-global-alert--{{type}}{{/if}} js-global-alert" role="alert">
+<div class="nsw-global-alert{{#if type}} nsw-global-alert--{{type}}{{/if}} js-global-alert" role="alert" data-cookie-name="{{cookie}}">
   <div class="nsw-global-alert__wrapper">
     <div class="nsw-global-alert__content">
       <div class="nsw-global-alert__title">{{title}}</div>

src/components/global-alert/blank.hbs

@@ -5,8 +5,8 @@ model:  json/global-alert.json
 ---
 
 {{>_global-alert model}}
-{{>_global-alert model type="light"}}
-{{>_global-alert model type="critical"}}
-{{>_global-alert model link="true"}}
-{{>_global-alert model link="true" type="light"}}
-{{>_global-alert model link="true" type="critical"}}
+{{>_global-alert model type="light" cookie="nsw-alert-light"}}
+{{>_global-alert model type="critical" cookie="nsw-alert-critical"}}
+{{>_global-alert model link="true" cookie="nsw-alert-link"}}
+{{>_global-alert model link="true" type="light" cookie="nsw-alert-light-link"}}
+{{>_global-alert model link="true" type="critical" cookie="nsw-alert-critical-link"}}

src/components/global-alert/global-alert.js

@@ -1,20 +1,49 @@
 class GlobalAlert {
   constructor(element) {
-    this.messageElement = element
-    this.closeButton = element.querySelector('.js-close-alert')
-    this.closeMessageEvent = (e) => this.closeMessage(e)
+    this.element = element
+    this.closeButton = this.element.querySelector('button.js-close-alert')
+    this.cookieName = this.element.getAttribute('data-cookie-name') || false
   }
 
   init() {
-    this.controls()
+    if (this.cookieName && this.constructor.getCookie(this.cookieName)) {
+      this.element.hidden = true
+      return
+    }
+    if (this.closeButton) {
+      this.controls()
+    }
   }
 
   controls() {
-    this.closeButton.addEventListener('click', this.closeMessageEvent, false)
+    this.closeButton.addEventListener('click', () => {
+      this.closeMessage()
+    })
   }
 
   closeMessage() {
-    this.messageElement.hidden = true
+    this.element.hidden = true
+    if (this.cookieName) {
+      this.constructor.setCookie(this.cookieName, 'dismissed', 7)
+    }
+  }
+
+  static setCookie(name, value, days) {
+    const date = new Date()
+    date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000))
+    const expires = `expires=${date.toUTCString()}`
+    document.cookie = `${name}=${value};${expires};path=/`
+  }
+
+  static getCookie(name) {
+    const nameEQ = `${name}=`
+    const ca = document.cookie.split(';')
+    for (let i = 0; i < ca.length; i += 1) {
+      let c = ca[i]
+      while (c.charAt(0) === ' ') c = c.substring(1, c.length)
+      if (c.indexOf(nameEQ) === 0) return c.substring(nameEQ.length, c.length)
+    }
+    return null
   }
 }