js: Extract pagination model.

* js/utils.js (guix.clamp): New function.
* js/controller/packages.js (guix.packages.controller): Remove 'pages',
  'currentPageIndex', and 'pageSize' properties.  Add 'pager' prop.
  Delete 'paginate', 'currentPage', 'isFirstPage', 'isLastPage', and
  'isCurrentPage' methods.
* js/model/packages.js (guix.packages.Pager): New function.
* js/view/packages.js (guix.packages.view): Use new Pager API.

1 files changed, 15 insertions, 32 deletions

diff --git a/js/controller/packages.js b/js/controller/packages.js
index db94d72..89f01e9 100644
--- a/js/controller/packages.js
+++ b/js/controller/packages.js
@@ -15,14 +15,19 @@
 // License along with this program.  If not, see
 // <http://www.gnu.org/licenses/>.
 
-(function(packages) {
+(function() {
+  var packages = guix.packages;
+
   packages.controller = (function() {
+    var PAGE_SIZE = 20;
+
+    function Pager(items) {
+      return new packages.Pager(items, PAGE_SIZE);
+    }
+
     function controller() {
       var self = this;
 
-      this.pages = m.prop([]);
-      this.currentPageIndex = 0;
-      this.pageSize = 20;
       this.searchTerm = m.prop("");
       this.columns = [
         { header: "Name", sortField: "name" },
@@ -43,40 +48,20 @@
         }
       ];
       this.sorter = m.prop(new packages.Sorter("name"));
+      this.pager = m.prop(Pager([]));
       this.phase = m.prop(packages.PHASE_NONE);
       this.selectedPackage = m.prop(null);
 
       this.packages = packages.Packages()
         .then(function(packages) {
           // All packages are visible initially
-          self.pages(self.paginate(packages, self.pageSize));
+          self.pager(Pager(packages));
         })
         .then(m.redraw);
     };
 
-
-    controller.prototype.paginate = function(array, pageSize) {
-      return guix.chunk(this.sorter().sort(array), pageSize);
-    };
-
-    controller.prototype.currentPage = function() {
-      return this.pages()[this.currentPageIndex] || [];
-    };
-
-    controller.prototype.isFirstPage = function() {
-      return this.currentPageIndex === 0;
-    };
-
-    controller.prototype.isLastPage = function() {
-      return this.currentPageIndex === this.pages().length - 1;
-    };
-
-    controller.prototype.isCurrentPage = function(i) {
-      return this.currentPageIndex === i;
-    };
-
     controller.prototype.packageCount = function() {
-      return this.pages().reduce(function(memo, page) {
+      return this.pager().pages.reduce(function(memo, page) {
         return memo + page.length;
       }, 0);
     };
@@ -84,12 +69,10 @@
     controller.prototype.doSearch = function() {
       var regexp = new RegExp(this.searchTerm(), "i");
 
-      this.pages(this.paginate(this.packages().filter(function(package) {
+      this.pager(Pager(this.packages().filter(function(package) {
         return regexp.test(package.name) ||
           regexp.test(package.synopsis);
-      }), this.pageSize));
-      // Reset pagination
-      this.currentPageIndex = 0;
+      })));
     };
 
     controller.prototype.sortBy = function(field) {
@@ -122,4 +105,4 @@
 
     return controller;
   })();
-})(guix.packages);
+})();