pattern: 
                "^/api/(apiName1|\
                apiName2|\
                apiName3)"

The above pattern supposed to be translated as

{ pattern: '^/api/(apiName1|apiName2|apiName3)' }

http://nodeca.github.io/js-yaml/

But it's translated with a space for line break as below:

{ pattern: '^/api/(apiName1| apiName2| apiName3)' }

It seems to me like a bug.

Thanks.