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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();
}
});
@wallin

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wallin commented Feb 11, 2013

Nice work! But I guess $shadow have to be removed when the scope is destroyed to not leave any orphan elements.

scope.$on('$destroy', function() {
 $shadow.remove();
});
@s1kx

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s1kx commented Jun 17, 2013

Thanks for this! You may wanna add wordWrap: 'break-word' to the css rules, so that it doesn't just overflow on long words.

@thomseddon

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thomseddon commented Jun 18, 2013

@s1kx Good tip, thanks

@maikeldaloo

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maikeldaloo commented Jul 2, 2013

This is very nice. It is perfect for what I'm doing now :)
My only suggestion would be to make the threshold a variable defined at the top.

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maikeldaloo commented Jul 2, 2013

Also, to make this work globally on every textarea without having to specify the 'auto-grow' directive, you can grab the following :)
I love AngularJS.

app.directive('textarea', function() {
    return {
        restrict: 'E',
        link: function( scope , element , attributes ) {
            var threshold    = 35,
                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 + threshold , minHeight ) );
            }

            scope.$on('$destroy', function() {
                $shadow.remove();
            });

            element.bind( 'keyup keydown keypress change' , update );
            update();
        }
    }
});
@julesbou

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julesbou commented Sep 27, 2013

Previous directive will not work if your textarea isn't visible. You can try:

  $.fn.getHiddenOffsetWidth = function () {
    // save a reference to a cloned element that can be measured
    var $hiddenElement = $(this).clone().appendTo($(this).parents(':visible').first());

    // calculate the width of the clone
    var width = $hiddenElement.outerWidth();

    // remove the clone from the DOM
    $hiddenElement.remove();

    return width;
  };

And replace:
width: element[0].offsetWidth - parseInt(paddingLeft || 0) - parseInt(paddingRight || 0),
with:
width: element.getHiddenOffsetWidth(),

@hmacha

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hmacha commented Nov 8, 2013

this is a comment

@nick-komick

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nick-komick commented Nov 15, 2013

I found that the CSS values for "top" and "left" did not work with the jqlite built into angular js. To use this code change the top and left values from -10000 to "-10000px".

If you use this code with the jquery library loaded, jquery will automatically append the "px" at the end of your value. However jqlite does not.

@paul-em

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paul-em commented Nov 17, 2013

i would also add 'word-wrap': 'break-word' to the list of properties

@bholzer

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bholzer commented Nov 26, 2013

I found that whenever the autogrow is attached to an element with an ng-binding, the directive runs before the bound data is put inside of the textarea.

This means that when you navigate to a page with a textarea already containing overflowing text from a binding, the textarea will be too small.

I fixed this by adding a timeout of 0 to the update call.

$timeout(update, 0) on line 54 will do the trick.

Don't forget to inject $timeout into the directive

@ingorammer

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ingorammer commented Nov 27, 2013

Instead of the $timeout-based version, another alternative would be to simply watch for model changes and resize the textarea accordingly:

if (attr.ngModel) {
   // update when the model changes
   scope.$watch(attr.ngModel, update);
}
@mismith

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mismith commented Jan 14, 2014

Thanks for all these guys! Some things worth noting:

  • If the width of the textarea can/will change (i.e. width: 100%), you must adjust the shadow width accordingly (so either on update() or on window.resize() or similar)
  • the Enter key introduces strange behaviour as either watching for ngModel change or keyup will only fire after the newline is added, which results in a brief clipping of the bottom line of text, assuming your threshold is set to 0. I've avoided this by hooking the keydown event and, if enter is pressed, appending a newline+non-breaking space to the textarea's value
  • finally, changing .replace(/\n$/, '<br/>&nbsp;') to .replace(/\n ?$/, '<br/>&nbsp;') (i.e. adding an optional space) will allow for more accurate accomodating of trailing whitespace
@alexilyaev

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alexilyaev commented Jan 16, 2014

Hi, this really helped me out, after trying other failing solutions.

May I ask why do we need the spaces replacement with /\s{2,}/g and the times function and everything?

What does it solve that this doesn't?
.replace(/\s/g, '&nbsp;')

@alexilyaev

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alexilyaev commented Jan 16, 2014

Also, why do we bind to keydown and keypress if they fire before the content change?
Isn't keyup enough here?

@murraybunton

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murraybunton commented Jan 25, 2014

This directive is super helpful, thanks!

@pafelin

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pafelin commented Mar 8, 2014

Hi, I read all the comments but i still have a small problem. When i have bind data to the text area it is too small. The update don't run. I tried with the $timeout solution and I checked the solution of @ingorammer with the attr.ngModel. Both don't work. For example when i tried adding a watcher for the attr.ngModel i saw that such an attribute don't exist.
This is what attr has:

$$element: x.fn.x.init[1]
$attr: Object          //here is missing the ngModel
    autoGrow: "auto-grow"
    class: "class"
    placeholder: "placeholder"
    style: "style"
    __proto__: Object
autoGrow: ""
class: "form-control parsley-validated"
placeholder: "Description"

and that's the way how i have it in the template:

<textarea data-auto-grow data-ng-model="task.description" placeholder="Description"></textarea>
@guidobouman

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guidobouman commented Mar 13, 2014

Still needs a lot of refinements but it a great start:
http://blog.justonepixel.com/geek/2013/08/14/angularjs-auto-expand/

Better approach than this shadow div thing...

@inspire22

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@boxxxie

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boxxxie commented Apr 7, 2014

I found https://github.com/monospaced/angular-elastic to be exactly what i was looking for.

@huyttq

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huyttq commented Jul 30, 2014

It could be simple like this :

appModule.directive('autoGrow', function() {
  return function(scope, element, attr){
    var update = function(event) {
      element.css('height', element[0].scrollHeight + 'px');
    }

    element.bind('keydown', update);
    update();
  }
});
@enapupe

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enapupe commented Aug 26, 2014

@huyttq perfect!
I'd say that keyup flows better than keydown.
Also it may need a shrink method..

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enapupe commented Aug 28, 2014

myApp.directive("autoGrow", function(){
    return function(scope, element, attr){
        var update = function(){
            element.css("height", "auto");
            element.css("height", element[0].scrollHeight + "px");
        };
        scope.$watch(attr.ngModel, function(){
            update();
        });
        attr.$set("ngTrim", "false");
    };
});
@rafenden

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rafenden commented Sep 7, 2014

@enapupe your directive jumps always to the top of textarea if its height is bigger that window height.

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enapupe commented Oct 17, 2014

@rafalenden would you fiddle your issue? My approach is at https://gist.github.com/enapupe/2a59589168f33ca405d0 , and has changed a bit.

@kimardenmiller

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kimardenmiller commented Jan 16, 2015

Inspired by @huyttq & @enapupe, with a fix to control initial height, in CoffeeScript:

autoGrow = ->
  (scope, element, attrs) ->
    update = ->
      if element[0].scrollWidth > element.outerWidth isBreaking = true else isBreaking = false
      element.css 'height', 'auto' if isBreaking
      height = element[0].scrollHeight
      element.css 'height', height + 'px'  if height > 0
    scope.$watch attrs.ngModel, update
    attrs.$set 'ngTrim', 'false'

# Register
App.Directives.directive 'autoGrow', autoGrow
@satyamsatyarthi

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satyamsatyarthi commented Jan 26, 2015

@enapupe & @rafalenden - The jump issue can be fixed by setting the window scroll position after the text area is resized. Not the most elegant or clean solution but it works.

http://stackoverflow.com/questions/18262729/how-to-stop-window-jumping-when-typing-in-autoresizing-textarea/18262927#18262927

.directive("autoGrow", ['$window', function($window){
    return {
        link: function (scope, element, attr, $window) {
            var update = function () {
                var scrollLeft, scrollTop;
                scrollTop = window.pageYOffset;
                scrollLeft = window.pageXOffset;

                element.css("height", "auto");
                var height = element[0].scrollHeight;
                if (height > 0) {
                    element.css("height", height + "px");
                }
                window.scrollTo(scrollLeft, scrollTop);
            };
            scope.$watch(attr.ngModel, function () {
                update();
            });
            attr.$set("ngTrim", "false");
        }
    };
}]);
@kevincobain2000

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kevincobain2000 commented Mar 12, 2015

how about visibility

     var $shadow = angular.element('<div></div>').css({
-      position: 'absolute',
-      top: -10000,
-      left: -10000,
+      visibility: "hidden",
       width: element[0].offsetWidth - parseInt(paddingLeft || 0) - parseInt(paddingRight || 0),
       fontSize: element.css('fontSize'),
       fontFamily: element.css('fontFamily'),

``
@LFDM

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LFDM commented Mar 20, 2015

It probably makes sense to avoid an angular watch here and listen to native events of the input/textarea field.

This also makes it possible to avoid messing around with the ngTrim setting.

function uiAutoGrow($window) {
    return {
        restrict: 'A',
        link: function (scope, element, attr) {
            element.on('input propertychange', update);

            function update() {
                var scrollTop = $window.pageYOffset,
                    scrollLeft = $window.pageXOffset;

                element.css('height', 'auto');
                var height = element[0].scrollHeight;

                if (height > 0) {
                    element.css('height', height + 'px');
                }

                $window.scrollTo(scrollLeft, scrollTop);
            }
        }
    };
}
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kevinleedrum commented Jun 5, 2015

For anyone else that finds this page, I used LFDM's solution, but I added 'overflow:hidden' css, and I added '$timeout(update)' to apply the update on page load as well (for previously saved form data).

function($window, $timeout) {
  return {
    restrict: 'A',
    link: function(scope, element, attr) {
      element.on('input propertychange', update);
      function update() {
          var scrollTop = $window.pageYOffset,
              scrollLeft = $window.pageXOffset;
          element.css({
            height: 'auto',
            overflow: 'hidden'
          });
          var height = element[0].scrollHeight;
          if (height > 0) {
              element.css('height', height + 'px');
          }
          $window.scrollTo(scrollLeft, scrollTop);
      }
      $timeout(update);
    }
  };
}
@Bloggerschmidt

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Bloggerschmidt commented Oct 16, 2015

@huyttq good work. thank you.

@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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