如果在把手模板中阻塞呼叫助手 [英] Calling Helper Within If Block in Handlebars Template

问题描述

 <$ 
 
我正在使用Handlebars.js模板引擎，并试图找出一种方法来做这样的事情c $ c> {{＃if itemSelectedSomeItem}} 
< div>选择了< / div> 
 {{/ if} 
  

其中 itemSelected
$ p $ Handlebars.registerHelper（itemSelected，function（item）{
var selected = false;
//确定是否选择项目的许多逻辑
返回选定;
}）;


尝试为模板使用此语法时出现错误，并且找不到任何示例之类的事情。我看到简单的#if块就像这样...

  {{＃if myValueInContext} 
< div> ;这将显示myValueInContext是否生成真值。< / div> 
 {{/ if}} 
  

但是，我无法弄清楚如何解决第一个例子。也许我正在接近这个错误。顺便说一下，我标记了这个胡须，因为我无法在问题中添加Handlebars标记。

解决方案

我认为这不会起作用。如果我理解handlebars文档是正确的，#if是一个已注册的block-helper，并且不会将另一个注册的helper作为参数。



根据您可能的文档像这样执行它



  
 Handlebars.registerHelper（'ifItemSelected'，function（item，block）{
 var selected = false; 
 //确定是否选择项目的逻辑很多
 
 if（selected）{
 return block（this）; 
} 
}）; 
  

之后您应该可以使用


  
 {{#ifItemSelected SomeItem}} 
这被选中
 {{/ ifItemSelected} 
  

但您必须确保 SomeItem 具有适当的格式。我没有看到在if语句中使用注册处理程序作为条件的方法。

I am working with Handlebars.js template engine and am trying to figure out a way to do something like this (contrived example):

{{#if itemSelected "SomeItem"}}
    <div>This was selected</div>
{{/if}

where itemSelected is a registered helper like this:

Handlebars.registerHelper("itemSelected", function(item) {
    var selected = false;
    // Lots of logic that determines if item is selected
    return selected;
});

I get errors when trying to use this syntax for the template, and I cannot find any example showing this kind of thing. I do see simple #if blocks like this...

{{#if myValueInContext}}
    <div>This will show if myValueInContext results in a truthy value.</div>
{{/if}}

But, I can't figure out how to tackle the first example. Maybe I am approaching this wrong.

By the way, I tagged this Mustache as I could not add a Handlebars tag to the question.

解决方案

I don't think this is going to work. If I understand the handlebars documentation correct, the #if is a registered block-helper itself and does not take another registered helper as an argument.

According to the documentation you might implement it like that

Handlebars.registerHelper('ifItemSelected', function(item, block) {
  var selected = false;
  // lots of logic that determines if item is selected

  if(selected) {
    return block(this);
  }
});

Afterwards you should be able to call it with

{{#ifItemSelected SomeItem}}
    This was selected
{{/ifItemSelected}

but you have to make sure SomeItem has the proper format. I don't see a way to use a registered handler as conditional in an if-statement.

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