I'm trying to validate Javascript code through Sonar and I have some doubts about strict mode rules.

The rule I'm validating is about "eval" and "arguments" behavior in strict mode.

In reading this rule description, it seems I can not assign arguments to new variable for accessing it later or in a loop.

On reading some documentation, from strict mode on Firefox and strict mode on IE the rules I found basically are (that apply to this case):

1. I can't have any variables/functions/etc named arguments since this is a reserved word.
2. arguments can't be bound

But, the sample code above seems to be violating that Sonar rule:

var args = arguments;

So, is this a false-positive or is this piece of code violating strict mode?

I'm trying to validate Javascript code through Sonar and I have some doubts about strict mode rules.

The rule I'm validating is about "eval" and "arguments" behavior in strict mode.

In reading this rule description, it seems I can not assign arguments to new variable for accessing it later or in a loop.

On reading some documentation, from strict mode on Firefox and strict mode on IE the rules I found basically are (that apply to this case):

1. I can't have any variables/functions/etc named arguments since this is a reserved word.
2. arguments can't be bound

But, the sample code above seems to be violating that Sonar rule:

var args = arguments;

So, is this a false-positive or is this piece of code violating strict mode?

• javascript
• strict

• Why do you think this is validating the rule? – dbarnes Commented Nov 21, 2013 at 17:38
• 1 I think it's not violating strict mode, you can have it. – Mahdi Commented Nov 21, 2013 at 17:40
• 1 It doesn't violate, you can check it yourself in console in developer tools. – vortexwolf Commented Nov 21, 2013 at 17:43
• 1 var args = arguments binds args, not arguments. The Sonar page you linked forbids binding arguments, and it seems to agree with the ECMAScript5 spec. (ecmascript/docs/tc39-2009-043.pdf, page 233) – psquared Commented Nov 21, 2013 at 17:49
• 1 I wouldn't be surprised if it's just being safe and not checking to see if args is used anywhere. I bet they made the assumption that args will be altered so you can't assign arguments to anything. – dbarnes Commented Nov 21, 2013 at 18:21

1 Answer 1

Based on the users answers and some researches, I've found this code (var args = arguments;) to be valid, since it's not modifying arguments, but only assigning it to another variable.

Please note that, since args now points to arguments it can't be modified also. But it can be read normally.

Update: Fix will be available under new release Javascript plugin (1.5).