JavaScript数组是喃？ AngularJS ngModel [英] JavaScript array is NaN? AngularJS ngModel

问题描述

我想看到的内容的ngModel的值是：

I'm trying to see what the value of an ngModel is:

.directive('myDir', function() {
  return {
    require: '?ngModel',
    link: function(scope, elm, attr, ngModel) {
      if (!ngModel)
        return

      console.log(ngModel)
      console.log(ngModel.$modelValue)
    }
  };
})

虽然我ngModel是它记录NaN的数组？

Even though my ngModel is an array it logs NaN?

推荐答案

$ viewValue 的和 $ modelValue 的默认为 Number.NaN - JavaScript的定义不 - 一个 - 号

$viewValue and $modelValue default to Number.NaN -- JavaScript Definition for Not - a - Number.

检查 Github上 ，你会发现

check Github and you find that

var NgModelController = ['$scope', '$exceptionHandler', '$attrs', 
                                 '$element', '$parse',
'$animate', '$timeout',
    function($scope, $exceptionHandler, $attr, $element, $parse, 
                   $animate, $timeout) 
  {
  this.$viewValue = Number.NaN;
  this.$modelValue = Number.NaN;

这是为什么convienient？因为 AngularJS 的试图避免像空案例和未定义。查看值和模型值绑定和范围中定义。这就是$范围服务点 - 管理modelValue和viewValue

Why is this convienient? Because AngularJS tries to avoid having cases like null and undefined. View Values and Model Values are bound and defined by "scope". That's the point of the $scope service -- to manage the modelValue and viewValue.

直到一个 AngularJS 的服务访问，它们将被默认为 number.NaN

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