server.R

server <- function(input, output) {

  # defining a reactive function
  # reacts to changes in the ngram slider
  # by taking it out of the output$wordcloud function
  # we have more control over when our dplyr statement
  # will get updated
  ngrams <- reactive({
  
    # the $<name> is used to reference the name
    # we gave our ngram sliderInput earlier
    input$ngramCount
  
  })
  
  # the $<name> here is referencing the name
  # we defined in the plotOutput('wordcloud')
  # earlier in the mainPanel
  output$wordcloud <- renderPlot({
  
    # our text is coming from the janeaustenr package
    austen_books() %>%
    
      # the %>% is a pipe operator
      # will take left side and pass it through
      # same as linux piping
      
      # selecting our column
      select(text) %>%
      
      # turning text into an ngram with count selected by user
      unnest_tokens(ngram, text, token="ngrams", n=ngrams()) %>%
      
      # getting occurence count of each ngram
      count(ngram)
      
      # setting up our wordcloud to use ngrams, sorted by count (n)
      # user can adjust max.words shown with slider
      with(wordcloud(ngram, n, max.words=input$cloudCount, rot.per=.2,
        colors=c("#b4b3b3", "#969696", "#484848", "#8dc7d3")
  
  })
}