From 05ed8a8c60c9086359c981f06ec7b9cebab23000 Mon Sep 17 00:00:00 2001
From: Anthony <ant@getme.co.uk>
Date: Mon, 13 Jul 2020 17:44:34 +0100
Subject: [PATCH] Improved track method to push the date picker above the input
 field if below will push it off screen

---
 module/date-picker.js    | 25 ++++++++++++++++++----
 package.json             |  2 +-
 scss/date_picker.scss    |  1 -
 spec/date-picker.spec.js | 45 +++++++++++++++++++++++++++++++++++++++-
 4 files changed, 66 insertions(+), 7 deletions(-)

diff --git a/module/date-picker.js b/module/date-picker.js
index 5f8f01f..78f559c 100644
--- a/module/date-picker.js
+++ b/module/date-picker.js
@@ -102,6 +102,12 @@ export class DatePicker {
                  */
                 'stayOpenOnPick': false,
 
+                /**
+                 * The vertical offset applied when tracking the date picker
+                 * to a field.
+                 */
+                'trackOffset': 10,
+
                 /**
                  * A list of weekday names used by the date picker.
                  */
@@ -412,12 +418,12 @@ export class DatePicker {
             this.calendar.date = date
         }
 
-        // Update the position of the picker inline with the associated input
-        this._track()
-
         // Show the date picker
         this.picker.classList.add(this.constructor.css['open'])
 
+        // Update the position of the picker inline with the associated input
+        this._track()
+
         // Flag the date picker as open
         this._open = true
 
@@ -450,10 +456,21 @@ export class DatePicker {
      * Position the date picker inline with the associated input element.
      */
     _track() {
+        const offset = this._options.trackOffset
+
         const rect = this.input.getBoundingClientRect()
         const top = rect.top + window.pageYOffset
         const left = rect.left + window.pageXOffset
-        this.picker.style.top = `${top + rect.height}px`
+
+        const pickerRect = this.picker.getBoundingClientRect()
+        const pickerBottom = top + pickerRect.height
+
+        if (pickerBottom > document.body.scrollHeight) {
+            console.log(top, pickerRect.height, offset)
+            this.picker.style.top = `${top - pickerRect.height - offset}px`
+        } else {
+            this.picker.style.top = `${top + rect.height + offset}px`
+        }
         this.picker.style.left = `${left}px`
     }
 }
diff --git a/package.json b/package.json
index 130b68a..ce81d32 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "manhattan-date-picker",
-  "version": "1.0.4",
+  "version": "1.0.5",
   "description": "Date parsing and picking for form fields.",
   "engines": {
     "node": ">=8.9.4"
diff --git a/scss/date_picker.scss b/scss/date_picker.scss
index 37240ef..a161f2f 100644
--- a/scss/date_picker.scss
+++ b/scss/date_picker.scss
@@ -5,7 +5,6 @@
     border: 1px solid #d4dce0;
     border-radius: 3px;
     display: none;
-    margin-top: 10px;
     position: absolute;
     width: 300px;
     z-index: 4;
diff --git a/spec/date-picker.spec.js b/spec/date-picker.spec.js
index cb333fa..420941f 100644
--- a/spec/date-picker.spec.js
+++ b/spec/date-picker.spec.js
@@ -568,7 +568,18 @@ describe('DatePicker', () => {
                     'height': 20,
                     'left': 30,
                     'right': 130,
-                    'top': 20,
+                    'top': 100,
+                    'width': 100
+                }
+            }
+
+            datePicker.picker.getBoundingClientRect = () => {
+                return {
+                    'bottom': 50,
+                    'height': 50,
+                    'left': 0,
+                    'right': 100,
+                    'top': 0,
                     'width': 100
                 }
             }
@@ -579,11 +590,43 @@ describe('DatePicker', () => {
 
         afterEach(() => {
             datePicker.destroy()
+
+            Object.defineProperty(
+                document.body,
+                'scrollHeight',
+                {
+                    'configurable': true,
+                    'value': 0
+                }
+            )
         })
 
         describe('track', () => {
 
             it('should position the picker inline with the input', () => {
+
+                Object.defineProperty(
+                    document.body,
+                    'scrollHeight',
+                    {
+                        'configurable': true,
+                        'value': 1000
+                    }
+                )
+
+                datePicker._track()
+                datePicker.picker.style.top.should.equal('140px')
+                datePicker.picker.style.left.should.equal('40px')
+
+                Object.defineProperty(
+                    document.body,
+                    'scrollHeight',
+                    {
+                        'configurable': true,
+                        'value': 120
+                    }
+                )
+
                 datePicker._track()
                 datePicker.picker.style.top.should.equal('50px')
                 datePicker.picker.style.left.should.equal('40px')