1235990 - JS typeof never returns "array"

Status: RESOLVED FIXED

(Firefox OS Graveyard :: General, defect)

Description

[Shu-yu Guo [:shu]]

I don't really know what component PersistentDataBlock is, sorry.

In my travels I have seen "array" being checked for when using the typeof operator. This is dead code.

b2g/components/test/unit/file_persistentdatablock.js
36:  } else if (typeof data === "array") {

b2g/components/PersistentDataBlock.jsm
68:  } else if (typeof data === "array") {

Comment 1

[:gerard-majax]

good point, I missed it

Comment 2

[Juan Gomez [:_AtilA_] (CET/CEST)]

Attachment: Correct array type checking using instanceof

Fixed!
There are lot of ways to check if the type is an Array and as we don't actually need to be crossbrowser compatible for internal Gecko code, we could use: Array.isArray() (EMACScript 5) as well... anyway, I followed the suggestion to use instanceof.

Comment 3

[Hannes Verschore [:h4writer]]

Comment on attachment 8705177 [details] [diff] [review]
Correct array type checking using instanceof

Review of attachment 8705177 [details] [diff] [review]:
-----------------------------------------------------------------

Just a question. Can we and would it make sense to add some tests that runs this code? Tests that would have caught this issue if present?

Comment 4

[Juan Gomez [:_AtilA_] (CET/CEST)]

Well, there's no specific tests for this function (toHexString). It's only used for logging purposes.
The component is being well tested here: http://mxr.mozilla.org/mozilla-central/source/b2g/components/test/unit/file_persistentdatablock.js

Comment 5

[Shu-yu Guo [:shu]]

Comment on attachment 8705177 [details] [diff] [review]
Correct array type checking using instanceof

Review of attachment 8705177 [details] [diff] [review]:
-----------------------------------------------------------------

Sorry for the delay, was on PTO.

Comment 6

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/dc0b2ddbdbb4

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/dc0b2ddbdbb4