javascript - 如果条件未在 ember 中传递正确的值

Question

我正在尝试在 embers js 中使用 if 条件。但值(value)没有正确传递。

如果条件

 {{#each item.model }}
     {{#ifCond item.title Raja}}
     <div>equal to</div>
     {{else}}
     <div>not equal to</div>  
     {{/ifCond}}
     {{/each}}

这是我的 HandleBar

Handlebars.registerHelper('ifCond', function (v1, v2, options) {

    alert(v1);

    if (v1 === v2) {
        return options.fn(this);

    }
    return options.inverse(this);
});

我的问题是警报显示值item.title

但我想要有值(value)的样本。

这是我的 Json

posts = [{
    title: "sample",
    body: "There are lots of à la carte software environments in this world."
}, {
    title: "Broken Promises",
    body: "James Coglan wrote a lengthy article about Promises in node.js."
}];

Answer 1

可以使用助手中的当前上下文来评估值。

示例，

http://emberjs.jsbin.com/dixokezafe/1/edit?html,js

hbs

<script type="text/x-handlebars" data-template-name="index">
{{#each model }}
 {{#ifCond title Raja}}
 <div>equal to</div>
 {{else}}
 <div>not equal to</div>  
 {{/ifCond}}
 {{/each}}

 <button {{action "addObject"}}> add random object</button>

js

App.IndexRoute = Ember.Route.extend({
  model: function() {
    return posts;
  }
});

App.IndexController = Em.ArrayController.extend({

  actions:{
    addObject:function(){
      this.get("model").pushObject({
    title: Math.floor(Math.random()*2)===0?"Raja":"something else",
    body: "James Coglan wrote a lengthy article about Promises in node.js."
});
    }
  }

});

var posts = [{
    title: "sample",
    body: "There are lots of à la carte software environments in this world."
}, {
    title: "Broken Promises",
    body: "James Coglan wrote a lengthy article about Promises in node.js."
},
            {
    title: "Raja",
    body: "James Coglan wrote a lengthy article about Promises in node.js."
}];

Handlebars.registerHelper('ifCond', function (v1, v2, options) {

  var _v1 = Em.get(this,v1);
  var _v2 = Em.get(this,v2);
v1 = Em.isEmpty(_v1)?v1:_v1;
  v2 = Em.isEmpty(_v2)?v2:_v2;
    if (v1 === v2) {
        return options.fn(this);

    }
    return options.inverse(this);
});

似乎无法注册绑定(bind)助手并以 block 形式使用它。查看一些包含解决此问题的有趣方法的链接。

http://discuss.emberjs.com/t/a-way-to-let-users-define-custom-made-bound-if-statements/2583

https://gist.github.com/slindberg/9924116

http://paarsgames.nl/2014/02/02/creating-your-own-custom-handlebars-bounded-ifs-in-ember/