AngularJs: How to pass part of my data from one co

问题:

I have an angular control that I use to display a set of data looking roughly like the following example. Apart from a unique block, it has a number of repeating (but discrete) blocks of the same structure.

{
  "person": {
    "lastName": "Bettertester",
    "firstName": "Fester",
    "address": "Out in the woods 17",
    "zipCode": "10666",
    "place": "Back of beyond"
  },
  "contact1": {
    "firstName": "Jane",
    "lastName": "Doe",
    "phone": "555-987-654",
    "relationship": "Aunt"
  },
  "contact2": {
    "firstName": "Kherumple",
    "lastName": "Whaduffle",
    "phone": "555-666-000",
    "relationship": "Imaginary friend"
  },
  "contact3": {
    "firstName": "Kherumple",
    "lastName": "Whaduffle",
    "phone": "555-666-000",
    "relationship": "Imaginary friend"
  }
}

I have written an angularjs component to retrieve and display this structure but want to hand the repeating block off to another component.

angular.module('myModule').component('mainComponent', {
  templateUrl : 'person.template.html',
  controller : [ '$scope', '$http', function mainController($scope, $http) {
    var self = this;
    self.data = null;
    $http.get(url).then(function(response) {
      self.data = response.data;
    }, function(response, status) {
      console.warn("Error while loading data");
      console.warn(" - response=", response);
      console.warn(" - status=", status);
      self.data = null;
    });
  } ]
});

The corresponding template:

<div>
  <h1>Person information</h1>
  <table>
  <tr>
    <th class="label-column">First & last name</th>
    <td class="data">{{$ctrl.data.person.firstName}} {{$ctrl.data.person.lastName}}</td>
  </tr>
  <tr>
    <th class="label-column">Address</th>
    <td class="data">{{$ctrl.data.person.address}}</td>
  </tr>
  <tr>
    <th class="label-column">ZIP code & Place</th>
    <td class="data">{{$ctrl.data.person.zipCode}} {{$ctrl.data.person.place}}</td>
  </tr>
  </table>

  <contact details="{{$ctrl.data.contact1}}"></contact> <!-- passing the details like this sort of works -->
  <contact details="{{$ctrl.data.contact2}}"></contact>
  <contact details="$ctrl.data.contact3"></contact>     <!-- passing the details like this does not work at all -->
</div>

The controller for the contact details looks as follows:

angular.module('myModule').component('contact', {
  templateUrl : 'contact.template.html',
  bindings : {
    details : '@'
  },
  controller : [ '$scope', '$http', function contactController($scope, $http) {
    var self = this;
    console.log("- details=", self.details);
  } ]
});

And the corresponding template:

<div>
  <h2>Contact</h2>
  <table>
  <!-- this works -->
  <tr>
    <th class="label-column">Everything</th>
    <td class="data">{{$ctrl.details}}</td>
  </tr>
  <tr>
    <th class="label-column">First & last name</th>
    <td class="data">{{$ctrl.details.firstName}} {{$ctrl.details.lastName}}</td>
  </tr>
  <tr>
    <th class="label-column">Phone</th>
    <td class="data">{{$ctrl.details.phone}}</td>
  </tr>
  <tr>
    <th class="label-column">Relationship</th>
    <td class="data">{{$ctrl.details.relationship}}</td>
  </tr>
  </table>

  <contact details="{{$ctrl.data.contact1}}"></contact>
  <contact details="{{$ctrl.data.contact2}}"></contact>
  <contact details="{{$ctrl.data.contact3}}"></contact>
  <contact details="{{$ctrl.data.contact4}}"></contact>
</div>

My questions is how to correctly pass the contact details that are part of the mainComponent to the contactComponent in a way that lets me access its fields in the corresponding template. If I pass them without the curly braces, the contact component does not seem to get any data at all. If I pass them with the curly braces, the contact component seems to get them in a way, but not as correct json object as I am unable to access fields within the contact block. I'm sure I'm missing something trivial but did not manage to find out where I go wrong.

回答1:

1. Use one-way < binding instead of interpolation @ binding because @ watches for interpolation and if there is no interpolation just passes the raw attribute string as the value itself. < or = binding watches for expression change and updates the template with the expression value correspondingly. In this particular case < is more convenient than = because we only need to watch input changes for component, we don't need that additional watch to affect parent back by changing the same expression.

2. After applying < use attribute values without curly braces safely.

3. Initialise your component logic in $onInit controller lifecycle hook, because this hook is called after the bindings have been initialised, which was the exact cause of why your console.log("- details=", this.details); was giving - details=undefined in contact controller.

Code Details:

let app = angular.module('app', []);

app.component('mainComponent', {
  template: `
  <div>
  <h1>Person information</h1>
  <table>
  <tr>
    <th class="label-column">First & last name</th>
    <td class="data">{{$ctrl.data.person.firstName}} {{$ctrl.data.person.lastName}}</td>
  </tr>
  <tr>
    <th class="label-column">Address</th>
    <td class="data">{{$ctrl.data.person.address}}</td>
  </tr>
  <tr>
    <th class="label-column">ZIP code & Place</th>
    <td class="data">{{$ctrl.data.person.zipCode}} {{$ctrl.data.person.place}}</td>
  </tr>
  </table>

  <contact details="$ctrl.data.contact1"></contact> <!-- passing the details like this sort of works -->
  <contact details="$ctrl.data.contact2"></contact>
  <contact details="$ctrl.data.contact3"></contact>     <!-- passing the details like this does not work at all -->
</div>
  `,
  controller: ['$scope', '$http', function mainController($scope, $http) {
  
    var self = this;
    
    self.$onInit = () => {
      self.data = {
        "person": {
          "lastName": "Bettertester",
          "firstName": "Fester",
          "address": "Out in the woods 17",
          "zipCode": "10666",
          "place": "Back of beyond"
        },
        "contact1": {
          "firstName": "Jane",
          "lastName": "Doe",
          "phone": "555-987-654",
          "relationship": "Aunt"
        },
        "contact2": {
          "firstName": "Kherumple",
          "lastName": "Whaduffle",
          "phone": "555-666-000",
          "relationship": "Imaginary friend"
        },
        "contact3": {
          "firstName": "Kherumple",
          "lastName": "Whaduffle",
          "phone": "555-666-000",
          "relationship": "Imaginary friend"
        }
      };
    };
    
  }]
});

app.component('contact', {
  template: `
    <div>
  <h2>Contact</h2>
  <table>
  <!-- this works -->
  <tr>
    <th class="label-column">Everything</th>
    <td class="data">{{$ctrl.details}}</td>
  </tr>
  <tr>
    <th class="label-column">First & last name</th>
    <td class="data">{{$ctrl.details.firstName}} {{$ctrl.details.lastName}}</td>
  </tr>
  <tr>
    <th class="label-column">Phone</th>
    <td class="data">{{$ctrl.details.phone}}</td>
  </tr>
  <tr>
    <th class="label-column">Relationship</th>
    <td class="data">{{$ctrl.details.relationship}}</td>
  </tr>
  </table>
</div>
  `,
  bindings: {
    details: '<'
  },
  controller: ['$scope', '$http', function jassMonitorHandController($scope, $http) {
    this.$onInit = () => {
      console.log("- details=", this.details);
    };
  }]
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.1/angular.min.js"></script>

<div ng-app="app">
    <main-component></main-component>
</div>

回答2:

The problem is the details binding in your contact component.

It should be details: '<' (one-way binding) instead of details: '@' (one time string binding). When using this type of binding, you won't need the curly braces in your template.

回答3:

I think that you could rewrite your component to receive the array of contacts and use the ng-repeat directive

<div ng-repeat='item in contactList'>
  <table>//your stuff</table>

Pass the data with bindings using the equal operator to receive the ng-model

bindings: '='

The last thing that I could suggest is to make a service to retrieve and store the data and inject in the corresponding component

Useful resources

• Components angular

• Angular style guide