Merge branch '21988-refactor-less-readable-existance-checking-code-from-coffeescript' into 'master'

Refactored less readable existance checks

## What does this MR do?
Clean up complex JavaScript expressions generated by conditional assignment and existence checks in CoffeeScript.
These are small changes that effect 1 or 2 lines at a time, but should make sections of code more readable.

## Are there points in the code the reviewer needs to double check?
Changes in [gl_dropdown.js](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/app/assets/javascripts/gl_dropdown.js) don't do much (largely just splitting stuff onto multiple lines). Is this a bit pointless?

## Why was this MR needed?
Auto-generated JS contains complex expressions that will be difficult to work with in future.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

A child issue of #21887 
Closes #21988

See merge request !6289

5 files changed, 20 insertions, 14 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c0324b15a5c..a36a6652ec8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ Please view this file on the master branch, on stable branches it's out of date.
   - Escape ref and path for relative links !6050 (winniehell)
   - Fixed link typo on /help/ui to Alerts section. !6915 (Sam Rose)
   - Fix filtering of milestones with quotes in title (airatshigapov)
+  - Refactor less readable existance checking code from CoffeeScript !6289 (jlogandavison)
   - Simpler arguments passed to named_route on toggle_award_url helper method
   - Fix typo in framework css class. !7086 (Daniel Voogsgerd)
   - Fix: Backup restore doesn't clear cache
diff --git a/app/assets/javascripts/awards_handler.js b/app/assets/javascripts/awards_handler.js
index d5966db0bf9..be26f406763 100644
--- a/app/assets/javascripts/awards_handler.js
+++ b/app/assets/javascripts/awards_handler.js
@@ -91,7 +91,7 @@
       css = {
         top: ($addBtn.offset().top + $addBtn.outerHeight()) + "px"
       };
-      if ((position != null) && position === 'right') {
+      if (position === 'right') {
         css.left = (($addBtn.offset().left - $menu.outerWidth()) + 20) + "px";
         $menu.addClass('is-aligned-right');
       } else {
diff --git a/app/assets/javascripts/gl_dropdown.js b/app/assets/javascripts/gl_dropdown.js
index 167979a55d9..4adcd00f716 100644
--- a/app/assets/javascripts/gl_dropdown.js
+++ b/app/assets/javascripts/gl_dropdown.js
@@ -208,7 +208,7 @@
     FILTER_INPUT = '.dropdown-input .dropdown-input-field';
 
     function GitLabDropdown(el1, options) {
-      var ref, ref1, ref2, ref3, searchFields, selector, self;
+      var searchFields, selector, self;
       this.el = el1;
       this.options = options;
       this.updateLabel = bind(this.updateLabel, this);
@@ -219,7 +219,11 @@
       selector = $(this.el).data("target");
       this.dropdown = selector != null ? $(selector) : $(this.el).parent();
       // Set Defaults
-      ref = this.options, this.filterInput = (ref1 = ref.filterInput) != null ? ref1 : this.getElement(FILTER_INPUT), this.highlight = (ref2 = ref.highlight) != null ? ref2 : false, this.filterInputBlur = (ref3 = ref.filterInputBlur) != null ? ref3 : true;
+      this.filterInput = this.options.filterInput || this.getElement(FILTER_INPUT);
+      this.highlight = !!this.options.highlight
+      this.filterInputBlur = this.options.filterInputBlur != null
+        ? this.options.filterInputBlur
+        : true;
       // If no input is passed create a default one
       self = this;
       // If selector was passed
@@ -418,7 +422,9 @@
       var $target;
       if (this.options.multiSelect) {
         $target = $(e.target);
-        if ($target && !$target.hasClass('dropdown-menu-close') && !$target.hasClass('dropdown-menu-close-icon') && !$target.data('is-link')) {
+        if ($target && !$target.hasClass('dropdown-menu-close') &&
+                       !$target.hasClass('dropdown-menu-close-icon') &&
+                       !$target.data('is-link')) {
           e.stopPropagation();
           return false;
         } else {
@@ -634,7 +640,9 @@
       }
 
       field = [];
-      value = this.options.id ? this.options.id(selectedObject, el) : selectedObject.id;
+      value = this.options.id
+        ? this.options.id(selectedObject, el)
+        : selectedObject.id;
       if (isInput) {
         field = $(this.el);
       } else if(value) {
diff --git a/app/assets/javascripts/graphs/stat_graph_contributors_graph.js b/app/assets/javascripts/graphs/stat_graph_contributors_graph.js
index 7d9d4d7c679..917c87a21a0 100644
--- a/app/assets/javascripts/graphs/stat_graph_contributors_graph.js
+++ b/app/assets/javascripts/graphs/stat_graph_contributors_graph.js
@@ -29,8 +29,7 @@
     ContributorsGraph.set_y_domain = function(data) {
       return ContributorsGraph.prototype.y_domain = [
         0, d3.max(data, function(d) {
-          var ref, ref1;
-          return d.commits = (ref = (ref1 = d.commits) != null ? ref1 : d.additions) != null ? ref : d.deletions;
+          return d.commits = d.commits || d.additions || d.deletions;
         })
       ];
     };
@@ -44,8 +43,7 @@
     ContributorsGraph.init_y_domain = function(data) {
       return ContributorsGraph.prototype.y_domain = [
         0, d3.max(data, function(d) {
-          var ref, ref1;
-          return d.commits = (ref = (ref1 = d.commits) != null ? ref1 : d.additions) != null ? ref : d.deletions;
+          return d.commits = d.commits || d.additions || d.deletions;
         })
       ];
     };
@@ -147,9 +145,8 @@
       return this.area = d3.svg.area().x(function(d) {
         return x(d.date);
       }).y0(this.height).y1(function(d) {
-        var ref, ref1, xa;
-        xa = d.commits = (ref = (ref1 = d.commits) != null ? ref1 : d.additions) != null ? ref : d.deletions;
-        return y(xa);
+        d.commits = d.commits || d.additions || d.deletions;
+        return y(d.commits);
       }).interpolate("basis");
     };
 
diff --git a/app/assets/javascripts/issuable_form.js b/app/assets/javascripts/issuable_form.js
index b7f92ae9883..15cfa756425 100644
--- a/app/assets/javascripts/issuable_form.js
+++ b/app/assets/javascripts/issuable_form.js
@@ -44,8 +44,8 @@
     };
 
     IssuableForm.prototype.handleSubmit = function() {
-      var ref, ref1;
-      if (((ref = parseInt((ref1 = this.issueMoveField) != null ? ref1.val() : void 0)) != null ? ref : 0) > 0) {
+      var fieldId = (this.issueMoveField != null) ? this.issueMoveField.val() : null;
+      if ((parseInt(fieldId) || 0) > 0) {
         if (!confirm(this.issueMoveConfirmMsg)) {
           return false;
         }