I dont know why toRemove return undefined

[zodman]

at

https://github.com/jakubpawlowicz/clean-css/blob/master/lib/properties/optimizer.js#L133

i fix with:

if ( typeof(toRemove) != 'undefined') {
    var longhandToShorthand = toRemove.name != _name;
} else {    
 continue;
}

[jakubpawlowicz]

It certainly should not be undefined, so your code snippet is worth having. However a reproducible test case would definitely be great to have - see https://github.com/jakubpawlowicz/clean-css/blob/master/CONTRIBUTING.md#pull-requests

[analytik]

Seems to work in Node.js v4.4.x, but is broken in 6.0, 6.5, 6.6 and possibly others. Tested on Windows 10 x64 and Debian x64.

[acidjazz]

confirmed w/ v6.9.1

/Users/k/256/node_modules/clean-css/lib/properties/optimizer.js:134
var longhandToShorthand = toRemove.name != _name;
^

TypeError: Cannot read property 'name' of undefined
at _optimize (/Users/k/256/node_modules/clean-css/lib/properties/optimizer.js:134:43)
at optimize (/Users/k/256/node_modules/clean-css/lib/properties/optimizer.js:198:3)
at recursivelyOptimizeProperties (/Users/k/256/node_modules/clean-css/lib/selectors/advanced.js:51:9)
at optimize (/Users/k/256/node_modules/clean-css/lib/selectors/advanced.js:61:3)
at minify (/Users/k/256/node_modules/clean-css/lib/clean.js:228:5)
at whenSourceMapReady (/Users/k/256/node_modules/clean-css/lib/clean.js:135:7)
at Object.whenDone (/Users/k/256/node_modules/clean-css/lib/clean.js:155:14)
at processNext (/Users/k/256/node_modules/clean-css/lib/imports/inliner.js:105:13)
at importFrom (/Users/k/256/node_modules/clean-css/lib/imports/inliner.js:79:10)
at ImportInliner.process (/Users/k/256/node_modules/clean-css/lib/imports/inliner.js:38:10)
at /Users/k/256/node_modules/clean-css/lib/clean.js:120:41
at _combinedTickCallback (internal/process/next_tick.js:67:7)
at process._tickCallback (internal/process/next_tick.js:98:9)

[jakubpawlowicz]

Again, it'd be great to have a reproducible test case, like a CSS snippet causing it.

[jakubpawlowicz]

Depends on #290 - aggressive merging should be out in 4.0.

[zodman]

@jakubpawlowicz i had a problem can you adviceme how to find the css that causing it ? a try with a lot printing values but no found the snippet

[jakubpawlowicz]

@zodman I'd start with printing properties first at https://github.com/jakubpawlowicz/clean-css/blob/3.4/lib/properties/optimizer.js#L133 and that should give you a clue what to look for.

Btw, you can also ditch aggressive merging altogether (--skip-aggressive-merging / aggressiveMerging: false) as it'll be gone in 4.0.

[zodman]

for some reason my gulpfile are minify a js file ...

stupid code!! long bug closed!

[jakubpawlowicz]

no worries 👍 glad you sorted it out