navigator.useragent reference lost in closure compiled js

Question

I was using a simple regex test like

is_safari_or_uiwebview = /(iPhone|iPod|iPad).*AppleWebKit/i.test(navigator.userAgent);

in my js. After compile it with Closure compiler (advanced optimization) it's not working anymore. It still give me the regex but navigator.useragent is missing.

Note, I'm not using closure library and do no intent to use at this point. How can I preserve this test?

js code

var browser_type = new RegExp('(iPhone|iPod|iPad).*AppleWebKit', 'i');
function is_safari_or_uiwebview() {
    return browser_type.test(navigator.userAgent);
}
window['is_safari_or_uiwebview'] = is_safari_or_uiwebview;

compiled code:

var l=/(iPhone|iPod|iPad).*AppleWebKit/i,l=/(iPhone|iPod|iPad).*AppleWebKit/i;function m(){return l.test(navigator.c)}window.is_safari_or_uiwebview=m;

Felix Kling · Accepted Answer · 2013-09-02T09:18:56.373

1

Simple solution: Use bracket notation, as explained in the documentation.

navigator['userAgent']

BUT, when I test your code in http://closure-compiler.appspot.com/home, it does not rename the property name with advanced compilation.

edited Sep 02 '13 at 09:18

answered Sep 02 '13 at 09:03

Felix Kling

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thanks! did not got this exact idea from there. now it works. – Ruben Trancoso Sep 02 '13 at 09:08
Sounds like some externs are missing, because that property should not be renamed like that. – Chad Killingsworth Sep 03 '13 at 13:42
1

@Chad: I was thinking the same. I thought that the compiler includes those "standard" externs by default. – Felix Kling Sep 03 '13 at 13:44
@FelixKling It does - but there are options to disable that such as `use_only_custom_externs` or by using a custom build of the compiler. – Chad Killingsworth Sep 03 '13 at 14:20

navigator.useragent reference lost in closure compiled js

1 Answers1