Handlebars.js if block helper == [英] Handlebars.js if block helper ==

问题描述

你如何改变下面的代码使其工作？问题是this =='some message'表达式：

 < ul> 
 {{#each errors}} 
 {{#if（this =='some message'）}} 
< li>状态< / li> 
 {{else}} 
< li> {{this}}< / li> 
 {{/ if}} 
 {{/ each}} 
< / ul> 
  

解决方案

最简单的事情是添加一个自定义 if_eq helper：

  Handlebars.registerHelper（'if_eq'，function（a， b，opts）{
 if（a == b）// Or ===根据您的需要
 return opts.fn（this）; 
 else 
 return opts。 inverse（this）; 
}）; 
  

然后调整您的模板：

 {{＃if_eq thissome message}} 
 ... 
 {{else}} 
 ... 
 {{/ if_eq}} 
  

演示： http://jsfiddle.net/ambiguous/d4adQ/

如果您的错误

code>条目不是简单的字符串，那么你可以添加这是一些消息标志给他们，并使用标准的 {{＃if}} 直接添加属性到一个字符串将无法正常工作）：

  for（var i = 0; i  errors [i] = {msg：errors [i]，is_status：errors [i] ==='some message'}; 
  

和：

  {{＃if is_status}} 
< li>状态< / li> 
 {{else}} 
< li> {{msg}}< / li> 
 {{/ if}} 
  

演示：

How would you change the following code to make it work? The problem is the this == 'some message' expression:

<ul>
  {{#each errors}}
    {{#if (this == 'some message') }}
    <li>Status</li>
    {{else}}
    <li>{{this}}</li>
    {{/if}}
  {{/each}}
</ul>

解决方案

The easiest thing would be to add a custom if_eq helper:

Handlebars.registerHelper('if_eq', function(a, b, opts) {
    if(a == b) // Or === depending on your needs
        return opts.fn(this);
    else
        return opts.inverse(this);
});

and then adjust your template:

{{#if_eq this "some message"}}
    ...
{{else}}
    ...
{{/if_eq}}

Demo: http://jsfiddle.net/ambiguous/d4adQ/

If your errors entries weren't simple strings then you could add "is this some message" flags to them and use a standard {{#if}} (note that adding a property directly to a string won't work that well):

for(var i = 0; i < errors.length; ++i)
    errors[i] = { msg: errors[i], is_status: errors[i] === 'some message' };

and:

{{#if is_status}}
    <li>Status</li>
{{else}}
    <li>{{msg}}</li>
{{/if}}

Demo: http://jsfiddle.net/ambiguous/9sFm7/

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