см. Документ изменение текста
Код разметки: -
<div class="ql-container ql-bubble" id="richTextQuel">
<ng-quill-editor theme="bubble" id="richTextEditor" placeholder="Inclusions" ng-model="title" modules="richTextEditorModules" class="ng-pristine ng-untouched ng-valid ng-isolate-scope ng-change="textChanged($event)"
ng-not-empty">
</ng-quill-editor>
</div>
Код Js: -
var limit = 5000;
quill.on('text-change', function(delta, old, source) {
if (quill.getLength() > limit) {
quill.deleteText(limit, quill.getLength());
}
});