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I have jslint plaining me to use || operator for below code,

query = ['browser' + (ieVersion ? ieVersion : 'UNKNOWN')]

I tried using || operator but that ends up in wrong result, 

query = ['browser' + ieVersion || 'UNKNOWN'] 
// => ['browserundefined']

I have jslint plaining me to use || operator for below code,

query = ['browser' + (ieVersion ? ieVersion : 'UNKNOWN')]

I tried using || operator but that ends up in wrong result, 

query = ['browser' + ieVersion || 'UNKNOWN'] 
// => ['browserundefined']
  • javascript
  • syntax
  • jslint
Share Improve this question edited Dec 18, 2012 at 18:01 Mahesh Kulkarni asked Dec 18, 2012 at 17:36 Mahesh KulkarniMahesh Kulkarni 3073 silver badges11 bronze badges 3
  • Sorry my bad, I did try with parentheses. Will update the question now – Mahesh Kulkarni Commented Dec 18, 2012 at 17:55
  • Um. But it works with parens, as in the answer you accepted. – Dave Newton Commented Dec 18, 2012 at 18:01
  • Edit: I screwed. I actually din't use brackets. I will always worry about precedence from now on. – Mahesh Kulkarni Commented Dec 18, 2012 at 18:01
Add a ment  | 

3 Answers 3

Reset to default 6

Operator precedence is wrong, try this:

query = ['browser' + (ieVersion || 'UNKNOWN')]

without extra parentheses + operator is stronger and JavaScript engine evaluates it as:

query = [('browser' + ieVersion) || 'UNKNOWN']

Notice that 'browser' + ieVersion is never falsy so you'll never see 'UNKNOWN'.

brackets?

query = ['browser' + (ieVersion || 'UNKNOWN')]

You need to wrap the expression in parentheses:

query = ['browser' + (ieVersion || 'UNKNOWN')]

本文标签： javascriptJslint use 3939 operator instead of conditional operatorStack Overflow

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