How to add Trend Lines in R Using Plotly - r

Question

I have a simple application in shiny and I would like to add to the trend lines. I know how to add a linear trend line using the lm and abline functions in ggplot, but how do I add trend lines in R Using only Plotly.
library(shiny)
library(plotly)
library(shinyWidgets)
set.seed(666)
df1 <- data.frame(Date = rep(seq(as.Date("2020-01-03"), by="day", len=12),10,replace = TRUE),
Product = rep(LETTERS[1:10], each = 12),
Value = sample(c(0:300),120, replace = T))
ui <- fluidPage(
pickerInput("All", "Choose", multiple = F, choices = unique(df1$Product) ,
options = list(`max-options` = 4,size = 10)),
plotlyOutput('plot')
)
server <- function(input, output) {
trend<- reactive({
df1 %>%
filter(Product %in% input$All) %>%
arrange(Date) %>%
droplevels()
})
output$plot <- renderPlotly({
plot_ly(data=trend(), x=~Date, y = ~Value,
type = 'scatter', mode = 'lines+markers')
})
}
shinyApp(ui = ui, server = server)

Answer 1

How about adding a line using linear regression?
library(shiny)
library(plotly)
library(shinyWidgets)
set.seed(666)
df1 <- data.frame(Date = rep(seq(as.Date("2020-01-03"), by="day", len=12),10,replace = TRUE),
Product = rep(LETTERS[1:10], each = 12),
Value = sample(c(0:300),120, replace = T))
ui <- fluidPage(
pickerInput("All", "Choose", multiple = F, choices = unique(df1$Product) ,
options = list(`max-options` = 4,size = 10)),
plotlyOutput('plot')
)
server <- function(input, output) {
trend<- reactive({
df1 %>%
filter(Product %in% input$All) %>%
arrange(Date) %>%
droplevels()
})
output$plot <- renderPlotly({
t <- trend()
m <- lm(Value~Date,data = t)
p <-plot_ly(data=t, x=~Date, y = ~Value,
type = 'scatter', mode = 'lines+markers')
p = add_lines(p, x=~Date, y=predict(m), name="Linear")
})
}
shinyApp(ui = ui, server = server)