CODEWITHSUNDEEP
javascriptjqueryangularjs
sooon
sooon

Reputation: 4888

Angularjs - TextArea autogrow

I want to use this directive in my project but I want the text area to expand the moment the content is loaded.

Angular-Autogrow.js:

(function(){
    'use strict';
    angular.module('angular-autogrow', []).directive('autogrow', ['$window', function($window){
        return {
            link: function($scope, $element, $attrs){

                /**
                 * Default settings
                 */
                $scope.attrs = {
                    rows: 1,
                    maxLines: 999
                };

                /**
                 * Merge defaults with user preferences
                 */
                for(var i in $scope.attrs){
                    if($attrs[i]){
                        $scope.attrs[i] = parseInt($attrs[i]);
                    }
                }

                /**
                 * Calculates the vertical padding of the element
                 * @returns {number}
                 */
                $scope.getOffset = function(){
                    var style = $window.getComputedStyle($element[0], null),
                        props = ['paddingTop', 'paddingBottom'],
                        offset = 0;

                    for(var i=0; i<props.length; i++){
                        offset += parseInt(style[props[i]]);
                    }
                    return offset;
                };

                /**
                 * Sets textarea height as exact height of content
                 * @returns {boolean}
                 */
                $scope.autogrowFn = function(){
                    var newHeight = 0, hasGrown = false;
                    if(($element[0].scrollHeight - $scope.offset) > $scope.maxAllowedHeight){
                        $element[0].style.overflowY = 'scroll';
                        newHeight = $scope.maxAllowedHeight;
                    }
                    else {
                        $element[0].style.overflowY = 'hidden';
                        $element[0].style.height = 'auto';
                        newHeight = $element[0].scrollHeight - $scope.offset;
                        hasGrown = true;
                    }
                    $element[0].style.height = newHeight + 'px';
                    return hasGrown;
                };

                $scope.offset = $scope.getOffset();
                $scope.lineHeight = ($element[0].scrollHeight / $scope.attrs.rows) - ($scope.offset / $scope.attrs.rows);
                $scope.maxAllowedHeight = ($scope.lineHeight * $scope.attrs.maxLines) - $scope.offset;

                $element[0].addEventListener('input', $scope.autogrowFn);
                /**
                 * Auto-resize when there's content on page load
                 */
                if($element[0].value != ''){
                    $scope.autogrowFn();
                }
            }
        }
    }]);
})();

I change:

// $element[0].addEventListener('input', $scope.autogrowFn);

  $element[0].addEventListener('load', $scope.autogrowFn);//<-- I add this line

but it did not work. How can I change it so that the text area automatically expand when the content is loaded?

Upvotes: 2

Views: 6215

Answers (3)

cat
cat

Reputation: 2895

As modern browsers support event.target there is also a minimal non angularjs alternative and you do not need to upgrade it to Angular later. Additionally there seems to be "this" (HTMLElement) accessible as a parameter. Using onscroll the textarea grows if it starts scrolling. Alternatives are onfocus or onkeyup events. Note that the textarea cannot shrink.

You may need to trigger a scroll event manually in a $watch if the model changes programmatically: htmlElement.dispatchEvent(new Event("scroll"));

https://jsfiddle.net/hnxd91rq/

<textarea onscroll="autogrowTextHeight(event, this)"></textarea>

<script>
function autogrowTextHeight(event, htmlElement) {
  // https://developer.mozilla.org/en-US/docs/Web/API/Event
  // var htmlElement = event.target; ... OR use this ...
  htmlElement.style.height = htmlElement.scrollHeight+"px";
}
</script>

Upvotes: 1

Gayathri Mohan
Gayathri Mohan

Reputation: 2962

Hi u have to use the directive first then include "angularjs-autogrow" the directive in app.js , then check the text area will auto grow based on you type

HTML

<textarea autogrow></textarea>

JS

var app = angular.module('plunker', ["angularjs-autogrow"]);

app.controller('MainCtrl', function($scope) {

});

for reference https://plnkr.co/edit/kj3ikS30cqVIRofTU22X?p=preview

Upvotes: 2

Aerus
Aerus

Reputation: 4380

My HTML is: 

<textarea autogrow ng-model="vm.myinput" ></textarea>

I replaced:

$element[0].addEventListener('input', $scope.autogrowFn);

with: 

$scope.$watch($attrs.ngModel, $scope.autogrowFn);

so every time the model is changed, the autogrow function is called. This should also work in your case.

Upvotes: 0

Related Questions