iteration order for Object
getify at gmail.com
Mon Mar 14 09:16:10 PDT 2011
> Aside from the JSON example of populating a dropdown list given (which I
> will agree is a real if contrived use case), there has been a lot of talk
> of "thousands of web developers" depending on preserving insertion order,
> but not one concrete example -- do you have one?
Two examples I've seen recently in projects, both relying primarily on the
for-in iteration order of an object:
1. exporting objects (like JSON, etc) to log files (server-side
log file output, like the "datetime" field first, etc. A variation on this
is using JSON.stringify(obj) and wanting the JSON output to have a reliable
output order, also for log files.
2. Using an object literal as a UI/form "configuration" where a each field
of the object represents a form element in a form-builder UI. If the
iteration order of the object is different in different engines/browsers,
the UI ends up being displayed in different orders.
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