SYWEB-12: You'll be needing this.

webclient/js/elastic.js

+/*
+ * angular-elastic v2.4.0
+ * (c) 2014 Monospaced http://monospaced.com
+ * License: MIT
+ */
+
+angular.module('monospaced.elastic', [])
+
+  .constant('msdElasticConfig', {
+    append: ''
+  })
+
+  .directive('msdElastic', [
+    '$timeout', '$window', 'msdElasticConfig',
+    function($timeout, $window, config) {
+      'use strict';
+
+      return {
+        require: 'ngModel',
+        restrict: 'A, C',
+        link: function(scope, element, attrs, ngModel) {
+
+          // cache a reference to the DOM element
+          var ta = element[0],
+              $ta = element;
+
+          // ensure the element is a textarea, and browser is capable
+          if (ta.nodeName !== 'TEXTAREA' || !$window.getComputedStyle) {
+            return;
+          }
+
+          // set these properties before measuring dimensions
+          $ta.css({
+            'overflow': 'hidden',
+            'overflow-y': 'hidden',
+            'word-wrap': 'break-word'
+          });
+
+          // force text reflow
+          var text = ta.value;
+          ta.value = '';
+          ta.value = text;
+
+          var append = attrs.msdElastic ? attrs.msdElastic.replace(/\\n/g, '\n') : config.append,
+              $win = angular.element($window),
+              mirrorInitStyle = 'position: absolute; top: -999px; right: auto; bottom: auto;' +
+                                'left: 0; overflow: hidden; -webkit-box-sizing: content-box;' +
+                                '-moz-box-sizing: content-box; box-sizing: content-box;' +
+                                'min-height: 0 !important; height: 0 !important; padding: 0;' +
+                                'word-wrap: break-word; border: 0;',
+              $mirror = angular.element('<textarea tabindex="-1" ' +
+                                        'style="' + mirrorInitStyle + '"/>').data('elastic', true),
+              mirror = $mirror[0],
+              taStyle = getComputedStyle(ta),
+              resize = taStyle.getPropertyValue('resize'),
+              borderBox = taStyle.getPropertyValue('box-sizing') === 'border-box' ||
+                          taStyle.getPropertyValue('-moz-box-sizing') === 'border-box' ||
+                          taStyle.getPropertyValue('-webkit-box-sizing') === 'border-box',
+              boxOuter = !borderBox ? {width: 0, height: 0} : {
+                            width:  parseInt(taStyle.getPropertyValue('border-right-width'), 10) +
+                                    parseInt(taStyle.getPropertyValue('padding-right'), 10) +
+                                    parseInt(taStyle.getPropertyValue('padding-left'), 10) +
+                                    parseInt(taStyle.getPropertyValue('border-left-width'), 10),
+                            height: parseInt(taStyle.getPropertyValue('border-top-width'), 10) +
+                                    parseInt(taStyle.getPropertyValue('padding-top'), 10) +
+                                    parseInt(taStyle.getPropertyValue('padding-bottom'), 10) +
+                                    parseInt(taStyle.getPropertyValue('border-bottom-width'), 10)
+                          },
+              minHeightValue = parseInt(taStyle.getPropertyValue('min-height'), 10),
+              heightValue = parseInt(taStyle.getPropertyValue('height'), 10),
+              minHeight = Math.max(minHeightValue, heightValue) - boxOuter.height,
+              maxHeight = parseInt(taStyle.getPropertyValue('max-height'), 10),
+              mirrored,
+              active,
+              copyStyle = ['font-family',
+                           'font-size',
+                           'font-weight',
+                           'font-style',
+                           'letter-spacing',
+                           'line-height',
+                           'text-transform',
+                           'word-spacing',
+                           'text-indent'];
+
+          // exit if elastic already applied (or is the mirror element)
+          if ($ta.data('elastic')) {
+            return;
+          }
+
+          // Opera returns max-height of -1 if not set
+          maxHeight = maxHeight && maxHeight > 0 ? maxHeight : 9e4;
+
+          // append mirror to the DOM
+          if (mirror.parentNode !== document.body) {
+            angular.element(document.body).append(mirror);
+          }
+
+          // set resize and apply elastic
+          $ta.css({
+            'resize': (resize === 'none' || resize === 'vertical') ? 'none' : 'horizontal'
+          }).data('elastic', true);
+
+          /*
+           * methods
+           */
+
+          function initMirror() {
+            var mirrorStyle = mirrorInitStyle;
+
+            mirrored = ta;
+            // copy the essential styles from the textarea to the mirror
+            taStyle = getComputedStyle(ta);
+            angular.forEach(copyStyle, function(val) {
+              mirrorStyle += val + ':' + taStyle.getPropertyValue(val) + ';';
+            });
+            mirror.setAttribute('style', mirrorStyle);
+          }
+
+          function adjust() {
+            var taHeight,
+                taComputedStyleWidth,
+                mirrorHeight,
+                width,
+                overflow;
+
+            if (mirrored !== ta) {
+              initMirror();
+            }
+
+            // active flag prevents actions in function from calling adjust again
+            if (!active) {
+              active = true;
+
+              mirror.value = ta.value + append; // optional whitespace to improve animation
+              mirror.style.overflowY = ta.style.overflowY;
+
+              taHeight = ta.style.height === '' ? 'auto' : parseInt(ta.style.height, 10);
+
+              taComputedStyleWidth = getComputedStyle(ta).getPropertyValue('width');
+
+              // ensure getComputedStyle has returned a readable 'used value' pixel width
+              if (taComputedStyleWidth.substr(taComputedStyleWidth.length - 2, 2) === 'px') {
+                // update mirror width in case the textarea width has changed
+                width = parseInt(taComputedStyleWidth, 10) - boxOuter.width;
+                mirror.style.width = width + 'px';
+              }
+
+              mirrorHeight = mirror.scrollHeight;
+
+              if (mirrorHeight > maxHeight) {
+                mirrorHeight = maxHeight;
+                overflow = 'scroll';
+              } else if (mirrorHeight < minHeight) {
+                mirrorHeight = minHeight;
+              }
+              mirrorHeight += boxOuter.height;
+
+              ta.style.overflowY = overflow || 'hidden';
+
+              if (taHeight !== mirrorHeight) {
+                ta.style.height = mirrorHeight + 'px';
+                scope.$emit('elastic:resize', $ta);
+              }
+
+              // small delay to prevent an infinite loop
+              $timeout(function() {
+                active = false;
+              }, 1);
+
+            }
+          }
+
+          function forceAdjust() {
+            active = false;
+            adjust();
+          }
+
+          /*
+           * initialise
+           */
+
+          // listen
+          if ('onpropertychange' in ta && 'oninput' in ta) {
+            // IE9
+            ta['oninput'] = ta.onkeyup = adjust;
+          } else {
+            ta['oninput'] = adjust;
+          }
+
+          $win.bind('resize', forceAdjust);
+
+          scope.$watch(function() {
+            return ngModel.$modelValue;
+          }, function(newValue) {
+            forceAdjust();
+          });
+
+          scope.$on('elastic:adjust', function() {
+            initMirror();
+            forceAdjust();
+          });
+
+          $timeout(adjust);
+
+          /*
+           * destroy
+           */
+
+          scope.$on('$destroy', function() {
+            $mirror.remove();
+            $win.unbind('resize', forceAdjust);
+          });
+        }
+      };
+    }
+  ]);