如果文本区域为空，则返回false Angular代码

Question

＆＃13;

＆＃13;

var myApp = angular.module("myApp", []);
myApp.controller("votesController", ['$scope', function($scope, $timeout) {
  $scope.comments = [
  ];
  $scope.newComment = {
    likes: 0
  };  
  $scope.createComment = function() {
    if ($scope.newComment.comment != "") {
      $scope.comments.push({
        comment: $scope.newComment.comment,
        likes: $scope.newComment.likes,
        likeColor : {},
        dislikeColor : {}
      });
    }
  };
  $scope.incrementLikes = function(comment) {
    comment.likes++;
  };
  $scope.decrementLikes = function(comment) {
    comment.likes--;
  };  
}]);

＆＃13;

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div class="container" ng-app="myApp">
  <div ng-controller="votesController">
    <div ng-repeat="comment in comments">
      <div class="comment_box_all">
        <div class="comment_user">
          <div class="comment_note">
            <a id="vote_comment" ng-click="incrementLikes(comment, $index)" class="vote_comment" ng-style="comment.likeColor">Like</a>
            <span class="num_vote_comm_11"> | {{comment.likes}} | </span>
            <a ng-click="decrementLikes(comment, $index)" class="vote_dis_like_comm" ng-style="comment.dislikeColor">Unlike</a>
          </div>
          <div class="content_text_user_ans"><span>{{comment.comment}}</span></div>
        </div>
      </div>
    </div>
    <div class="area_comm_tex">
      <textarea class="text_area" ng-model="newComment.comment" placeholder="Add comment"></textarea>
      <button class="op_comm_now" ng-click="createComment()">Add text</button>
    </div>
  </div>
</div>

＆＃13;

＆＃13;

＆＃13;

嘿，现在这是添加文本的脚本，可以计算喜欢或不喜欢点击，但是是一个问题，即使文本区域为空（如添加/不喜欢），此代码也会变差。

问题：如果文本区域为空（没有任何字符，例如trim（）），那么该代码如何才能返回false？

Answer 1

你可以这样做：

PremiereData

Answer 2

您应该初始化$ scope.newComment.comment，使其不是未定义。

var myApp = angular.module("myApp", []);
myApp.controller("votesController", ['$scope', function($scope, $timeout) {
  $scope.comments = [
  ];
  $scope.newComment = {
    likes: 0,
    comment:""
  };  
  $scope.createComment = function() {
    if ($scope.newComment.comment != "") {
      $scope.comments.push({
        comment: $scope.newComment.comment,
        likes: $scope.newComment.likes,
        likeColor : {},
        dislikeColor : {}
      });
    }
  };
  $scope.incrementLikes = function(comment) {
    comment.likes++;
  };
  $scope.decrementLikes = function(comment) {
    comment.likes--;
  };  
}]);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div class="container" ng-app="myApp">
  <div ng-controller="votesController">
    <div ng-repeat="comment in comments">
      <div class="comment_box_all">
        <div class="comment_user">
          <div class="comment_note">
            <a id="vote_comment" ng-click="incrementLikes(comment, $index)" class="vote_comment" ng-style="comment.likeColor">Like</a>
            <span class="num_vote_comm_11"> | {{comment.likes}} | </span>
            <a ng-click="decrementLikes(comment, $index)" class="vote_dis_like_comm" ng-style="comment.dislikeColor">Unlike</a>
          </div>
          <div class="content_text_user_ans"><span>{{comment.comment}}</span></div>
        </div>
      </div>
    </div>
    <div class="area_comm_tex">
      <textarea class="text_area" ng-model="newComment.comment" placeholder="Add comment"></textarea>
      <button class="op_comm_now" ng-click="createComment()">Add text</button>
    </div>
  </div>
</div>

Answer 3

var myApp = angular.module("myApp", []);
myApp.controller("votesController", ['$scope', function($scope, $timeout) {
  $scope.comments = [
  ];
  $scope.newComment = {
    likes: 0
  };  
  $scope.createComment = function() {
    if ($scope.newComment.comment != "") {
      $scope.comments.push({
        comment: $scope.newComment.comment,
        likes: $scope.newComment.likes,
        likeColor : {},
        dislikeColor : {}
      });
    }
  };
  $scope.incrementLikes = function(comment) {
  if($scope.newComment.comment && $scope.newComment.comment.length){
   comment.likes++;
  }

  };
  $scope.decrementLikes = function(comment) {
if($scope.newComment.comment && $scope.newComment.comment.length){
    comment.likes--;
}
  };  
}]);

您首先检查文本是否为空。如果文本为空，请执行增量或减量。