Vader is a lexicon and rule-based sentiment analysis tool that is specifically attuned to sentiments expressed in social media.
You can install the released version of vader from CRAN with:
install.packages("vader")
N.B. "Yesn't" is an internet neologism meaning "no", "maybe yes, maybe no", "didn't", etc.
library(vader) get_vader("I yesn't like it")
###doesn't include non-dictionary contractions when calculating negations get_vader("I yesn't like it", incl_nt = F)
###doesn't include neutral words in calculations get_vader("I yesn't like it", neu_set = F)