Too Long; Didn't Read
Recently I got into a <a href="http://disq.us/p/1jvymj2" target="_blank">discussion</a> about how to decide a function is pure in JavaScript. The whole concept of pureness seems to be blurry in such a dynamic language. The following examples show we might need to redefine the term ‘pure function’, or — at least–be very careful when we decide on it.