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https://issues.apache.org/jira/browse/FLEX-34984?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Piotr Zarzycki updated FLEX-34984:
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Fix Version/s: (was: Apache FlexJS 0.6.0)
Apache FalconJX 0.6.0
> for-each loops cross-compile incorrectly
> ----------------------------------------
>
> Key: FLEX-34984
> URL: https://issues.apache.org/jira/browse/FLEX-34984
> Project: Apache Flex
> Issue Type: Bug
> Components: Falcon, FlexJS
> Affects Versions: Apache FlexJS 0.5.0
> Reporter: Andy Dufilie
> Assignee: Alex Harui
> Fix For: Apache FalconJX 0.6.0
>
>
> When you write a for-each loop, the iterable gets re-evaluated on every
> iteration.
> Example code:
> {code}
> for each (var item:Object in Test.getItems()) {
> Test.doSomething(item);
> }
> {code}
> Cross-compiled:
> {code}
> for (var foreachiter0 in Test.getItems())
> {
> var item = Test.getItems()[foreachiter0];
> {
> Test.doSomething(item);
> }}
> {code}
> It should not call Test.getItems() on every loop iteration. Instead, it
> should generate a new local variable prior to entering the loop to store the
> result:
> {code}
> var foreachiter0_target = Test.getItems();
> for (var foreachiter0 in foreachiter0_target)
> {
> var item = foreachiter0_target[foreachiter0];
> Test.doSomething(item);
> }
> {code}
> I can see problematic code in three places:
> * JSGeneratingReducer.java:
> https://github.com/apache/flex-falcon/blob/develop/compiler.js/src/org/apache/flex/compiler/internal/as/codegen/JSGeneratingReducer.java#L3426
> * ForEachEmitter.java:
> https://github.com/apache/flex-falcon/blob/develop/compiler.jx/src/org/apache/flex/compiler/internal/codegen/js/jx/ForEachEmitter.java
> * JSVF2JSEmitter.java:
> https://github.com/apache/flex-falcon/blob/develop/compiler.jx/src/org/apache/flex/compiler/internal/codegen/js/vf2js/JSVF2JSEmitter.java#L1708
> Another solution would be to use a for...of loop, Standard in ES6, though
> that won't work in Internet Explorer:
> https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of
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