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Auto Expanding/Grow textarea directive for AngularJS
/**
* The MIT License (MIT)
*
* Copyright (c) 2013 Thom Seddon
* Copyright (c) 2010 Google
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
* Adapted from: http://code.google.com/p/gaequery/source/browse/trunk/src/static/scripts/jquery.autogrow-textarea.js
*
* Works nicely with the following styles:
* textarea {
* resize: none;
* word-wrap: break-word;
* transition: 0.05s;
* -moz-transition: 0.05s;
* -webkit-transition: 0.05s;
* -o-transition: 0.05s;
* }
*
* Usage: <textarea auto-grow></textarea>
*/
app.directive('autoGrow', function() {
return function(scope, element, attr){
var minHeight = element[0].offsetHeight,
paddingLeft = element.css('paddingLeft'),
paddingRight = element.css('paddingRight');
var $shadow = angular.element('<div></div>').css({
position: 'absolute',
top: -10000,
left: -10000,
width: element[0].offsetWidth - parseInt(paddingLeft || 0) - parseInt(paddingRight || 0),
fontSize: element.css('fontSize'),
fontFamily: element.css('fontFamily'),
lineHeight: element.css('lineHeight'),
resize: 'none'
});
angular.element(document.body).append($shadow);
var update = function() {
var times = function(string, number) {
for (var i = 0, r = ''; i < number; i++) {
r += string;
}
return r;
}
var val = element.val().replace(/</g, '&lt;')
.replace(/>/g, '&gt;')
.replace(/&/g, '&amp;')
.replace(/\n$/, '<br/>&nbsp;')
.replace(/\n/g, '<br/>')
.replace(/\s{2,}/g, function(space) { return times('&nbsp;', space.length - 1) + ' ' });
$shadow.html(val);
element.css('height', Math.max($shadow[0].offsetHeight + 10 /* the "threshold" */, minHeight) + 'px');
}
element.bind('keyup keydown keypress change', update);
update();
}
});
@i-kaplin
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i-kaplin commented Oct 26, 2015

@kevinleedrum Thanks for your solution. Helped me.

@sunabozu
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sunabozu commented Nov 1, 2015

@LFDM Thanks, your solution is quite elegant. Although you may want to add focus event, so you can expand textarea by entering it, when you loaded a page and have some text inside it already.

@Dima-HAN
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Dima-HAN commented Jan 4, 2016

Good solution, I would change event handler a bit to handle paste event with the right mouse button, which is often used to copy paste stuff

element.bind('keyup paste', function(){setTimeout(update, 0);});

@dany28
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dany28 commented Apr 21, 2016

my solution, for angular and bootstrap with form-control class, using shadow textarea (without fixing input data)

function autoGrow() {
    return {
        restrict: 'A',
        link: function (scope, element, attr, ctrl) {
            var minHeight = element[0].offsetHeight;

            //create shadow textarea
            var $shadowtx = angular.element('<textarea></textarea>').css({
                position: 'absolute',
                top: -10000,
                left: -10000,
                resize: 'none',

            });
            element.css({resize: "none"}).parent().css({ position: "relative" });
            $shadowtx.addClass("form-control");
            //add to element parent
            angular.element(element.parent()[0]).append($shadowtx);

            var update = function (addtext) {
                addtext = addtext || " aaa"; //when line is ending show new line
                $shadowtx.val(element.val() + addtext);
                element.css('height', Math.max($shadowtx[0].scrollHeight + 5 /* the "threshold" */, minHeight) + 'px');
            }

            //on enter catch keydown, but simulate adding enter
            element.bind('keydown', function (event) {
                var keyc = event.keyCode || event.which;
                if (keyc == 13) {
                    update("\n aaa");
                }
            }).bind('keyup', function (event) {
                var keyc = event.keyCode || event.which;
                document.title = keyc;
                if ((keyc == 46) || (keyc==8)) { //delete, backspace, not fired by scope.$watch
                    update();
                }
            });

            //watch model binding
            scope.$watch(attr['ngModel'], function (v) {
                update();
            });
            //watch show
            scope.$watch(attr['ngShow'], function (v) {
                update();
            });

            update();
        }
    };
};

@symonny
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symonny commented Apr 29, 2016

Thanks . my adjusted version added below makes sure that there are no extra spaces added under the text

  • I used $timeout to make sure the shadow element's sizes are set after the current element is rendered and we have the correct size of the text
  • For textarea style i have set a height / min-height:
textarea{resize: none; box-sizing: content-box; height: auto; overflow: hidden;}
textarea.form-control{ min-height: 16px; height: 16px;  width: 100%;  }

  • Sample usage

<textarea class="form-control word-wrap" auto-size placeholder="Set Location…" ng-model="item.address" ui-focus="isInTabFocus(listIndex, 1)" tabindex="{{getTabIndex(listIndex,1)}}"></textarea>

  • sample result
    screen shot 2016-04-28 at 6 58 26 pm

    .directive('autoSize', ['$timeout', function($timeout) {
      return function (scope, element, attr, ctrl) {
        var minHeight;
        var $shadowtx = angular.element("<textarea class='" + attr['class'] + "'></textarea>");
        //add to element parent
        angular.element(element.parent()[0]).append($shadowtx);
        element.css({resize: "none"}).parent().css({ position: "relative" });
    
        var update = function (addtext) {
          $shadowtx.val(element.val() + (addtext ? addtext: ''));
          element.css('height', Math.max($shadowtx[0].scrollHeight, minHeight) + 'px');
        };
    
        element.bind('keydown', function (event) {
          var keyc = event.keyCode || event.which;
          if (keyc == 13) {
            update("\n");
          }
        }).bind('keyup', function (event) {
          var keyc = event.keyCode || event.which;
          if ((keyc == 46) || (keyc==8)) { //delete, backspace, not fired by scope.$watch
            update();
          }
        });
    
        $timeout(function(){
          minHeight = element[0].offsetHeight;
          $shadowtx.css({
            position: 'absolute',
            top: -10000,
            left: -10000,
            resize: 'none',
            width: element.width(),
            height: element.height()
          });
          update();
        }, 0);
    
        scope.$watch(attr['ngModel'], function(v){update();});
      }
    }]);
    

@moshewe
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moshewe commented Jul 6, 2016

@symonny - works great OOTB. Nice!

@kuldeepiitg
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kuldeepiitg commented Sep 4, 2016

It doesn't work if ng-model is set by code (controller). Like I fetch text from server and set it there on success so it doesn't set proper height.

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