library(httr2)

# Read both funds' files; each has the date of its own issuer's file
funds <- list()
for (ticker in c("VOO", "QQQ")) {
  url <- paste0("https://tickerinside.com/api/v1/fund/", tolower(ticker),
                ".json")
  funds[[ticker]] <- request(url) |>
    req_user_agent("MyProject/1.0 (+https://example.com)") |>
    req_perform() |>
    resp_body_json()
  writeLines(paste(ticker, "holdings_as_of", funds[[ticker]]$holdings_as_of))
}

# Overlap by weight, as the site computes it: for every ticker both funds
# hold, add the smaller of its two weights
a <- unlist(funds$VOO$holdings)
b <- unlist(funds$QQQ$holdings)
shared <- intersect(names(a), names(b))
overlap <- sum(pmin(a[shared], b[shared]))
writeLines(sprintf("overlap by weight %.1f%%, %d companies in both",
                   overlap, length(shared)))

# The lines to print under the figure, one per fund file
for (fund in funds) writeLines(fund$cite_as)