Modify chart_Series theme

Question

I am trying to change the colours of the bars using the theme argument, but I get an error:

library(quantmod)
getSymbols("SPY", from=Sys.Date()-500, to=Sys.Date())
chart_Series(SPY)
chart_Series(SPY,theme=chart_theme(dn.col = "cyan"))
# Error in chart_theme(dn.col = "cyan") : unused argument (dn.col = "cyan")

Answer 1

Look at the code. chart_theme takes no arguments, so trying chart_theme(dn.col="cyan") makes no sense.

> args(chart_theme)
function () 
NULL

chart_theme() returns a list and you want to modify portions of it, so just do that.

myTheme <- chart_theme()
myTheme$col$dn.col <- "cyan"
chart_Series(SPY,theme=myTheme)