Talk:Immediately invoked function expression
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Invalid Example
[edit]Note that code samples from Alman's page are licensed under the GPL and so may be used with attribution.
This code snippet is incorrect:
var v, getValue;
v = 1;
getValue = (function(v) {
return v;
}(v));
v = 2;
getValue(); // 1
`getValue` is the number 1, not a function. 88.90.244.215 (talk) 19:40, 3 April 2013 (UTC) Later yo
ES6 Block Scope
[edit]ES6 block scope and let/ const replaces some use cases of IIFE and may need to be mentioned in this article.
- IEFEs blocks cannot replace the module pattern. Blocks don't have return values so IIFE is needed for objects that have private state.
- For function declaration scoping an IIFE is still necessary because it will be hoisted out of a block scope.
See: https://stackoverflow.com/questions/33534485/will-const-and-let-make-the-iife-pattern-unnecessary — Preceding unsigned comment added by Jpvosloo (talk • contribs) 01:47, 19 February 2020 (UTC)
Parentheses
[edit]The Usage section says: a common convention is to enclose both the function expression and invocation in parentheses but the following example (the one with the parameters) does not follow this convention (the invocation is not enclosed).
I changed that example in order to have both expression and invocation enclosed in parentheses. --Mariana de El Mondongo (talk) 00:28, 24 February 2015 (UTC)
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Thank you. The Transhumanist 01:09, 12 April 2017 (UTC)
One-time initialization with garbage collected resources
[edit]How strange this is not mentioned. One of the frequent reasons to use IIFE's is initialization code. Especially when resources are used that can be discarded after initialization is done. Afterwards, the function and its internal variables are available to be garbage-collected. As one not-so-good tutorial mentions:
- The variable and functions that were declared in the scope of IIFE are available for garbage collection, once the IIFE is executed. Hence managing Memory in an efficient manner and ensures that the function and variables do not bind itself to the global scope.
Shenme (talk) 05:09, 20 June 2018 (UTC)
Initial explanation
[edit]The initial explanation is not readily understandable and needs to be greatly simplified. (Put another way, it would only be understandable by someone who didn't need to view this page.) A more technical explanation can follow afterward. — Preceding unsigned comment added by 203.161.100.28 (talk) 06:46, 1 November 2018 (UTC)
other languages that support IIFE
[edit]PHP has the same syntax for IIFE as JavaScript:
<?php (function(){ echo "Hello from IIFE"; })();
and you can make an IIFE in C++ like:
([]()->void{ std::cout << "Hello from IIFE"; })();
Rust also supports this, which is useful for scoping errors:
(|| {
do_thing_one()?;
do_thing_two()?;
Ok(())
})().map_err(CustomError::ThisError)?;