这种自调用匿名函数变体背后的原因
在查看 github 上的 code 时,我发现了以下内容:
While looking at code on github, I found the following:
(function() {
}).call(this);
这显然是一个自调用匿名函数.但是为什么会这样写呢?我习惯于看到规范的变体 (function() {})()
.
This is clearly a self invoking anonymous function. But why is it written this way? I'm used to seeing the canonical variant (function() {})()
.
将 .call(this)
用于自调用匿名函数有什么特别的优势吗?
Is there any particular advantage to using .call(this)
for a self invoking anonymous function?
看起来一些 commonjs 环境将 this
设置为模块顶层的非全局值.哪些,以及他们将 this
设置为您可能想要保留的内容?
It looks like some commonjs environments set this
to a non-global value at the top level of a module. Which ones, and what do they set this
to that you might want to preserve?
推荐答案
.call(this)
(实际上只是 ()
直到我改变它)确保你的顶级级别 this
通过严格模式保持一致,--bare
选项和/或运行环境(顶级 this
不指向全局对象).
.call(this)
(was actually just ()
until I changed it) ensures your top level this
to be consistent through strict mode, --bare
option and/or the running environment (where top level this
doesn't point to global object).
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