無法理解handlebars.js上下文

Question

我在理解上下文如何在handlebars.js中工作時遇到了麻煩，特別是“ ../”符號。 我放在一起的jsfiddle最好地體現了這一點：

http://jsfiddle.net/accelerate/AwChe/

內容：

"rootvar": "hi",
"mydata": [{
    "renderme": true,
    "mytext": "bye"
}]

模板：

rootvar = {{{rootvar}}} (should be "hi")<br/>
{{#each mydata}}
<br/>In mydata...<br/>
rootvar = {{{rootvar}}} (should be empty)<br/>
rootvar = {{{../rootvar}}} (should be "hi")<br/>
mytext = {{{mytext}}} (should be "bye")<br/>
{{#if renderme}}
<br/>In renderme...<br/>
rootvar = {{{rootvar}}} (should be empty)<br/>
rootvar = {{{../rootvar}}} (should be empty)<br/>
rootvar = {{{../../rootvar}}} (should be "hi")<br/>
mytext = {{{mytext}}} (should be empty!!)<br/>
mytext = {{{../mytext}}} (should be "bye")<br/>
{{/if}}
{{/each}}

輸出：

rootvar = hi (should be "hi")

In mydata...
rootvar = (should be empty)
rootvar = hi (should be "hi")
mytext = bye (should be "bye")

In renderme...
rootvar = (should be empty)
rootvar = (should be empty)
rootvar = hi (should be "hi")
mytext = bye (should be empty!!)
mytext = bye (should be "bye")

換句話說，我在#each語句中嵌套了一個#if語句。 我可以理解為什么我需要使用“ ../../rootvar”來訪問“ rootvar”。 我不明白的是為什么我不需要執行“ ../”來訪問當前mydata元素中的其他變量。 我是否不需要像#rootvar一樣去#if的父上下文來訪問“ mytext”？ 如果我不這樣做，那為什么“ ../mytext”也能起作用？

Answer 1

#if helper這是正常的，因為它保留了上下文。

//here context is:
//  "rootvar": "hi",
//  "mydata": [{
//  "renderme": true,
//  "mytext": "bye" }]
rootvar = {{{rootvar}}} (should be "hi")<br/>
{{#each mydata}}
// here `each` will change the context to each item in 'mydata' so it becomes
//   { "renderme": true,
//     "mytext": "bye" }
<br/>In mydata...<br/>
rootvar = {{{rootvar}}} (should be empty)<br/>
rootvar = {{{../rootvar}}} (should be "hi")<br/>
mytext = {{{mytext}}} (should be "bye")<br/>
{{#if renderme}}
// now `if` will create new context but it is the same as the parent context
//     { "renderme": true,
//     "mytext": "bye" }
<br/>In renderme...<br/>
rootvar = {{{rootvar}}} (should be empty)<br/>
rootvar = {{{../rootvar}}} (should be empty)<br/>
rootvar = {{{../../rootvar}}} (should be "hi")<br/>
mytext = {{{mytext}}} (should be "bye")<br/>
mytext = {{{../mytext}}} (should be "bye")<br/>
{{/if}}
{{/each}}

有關更多詳細信息，請參見此github問題 。