Crosstalk (original) (raw)

Crosstalk is an add-on to the htmlwidgets package. It extends htmlwidgets with a set of classes, functions, and conventions for implementing cross-widget interactions (currently, linked brushing and filtering).

Play with the example below by manipulating the slider, clicking rows in the data table, and playing with the selection button in the map.

Magnitude 

---
title: Fiji earthquakes
output: html_document
---

```{r}
library(crosstalk)
library(leaflet)
library(DT)

# Wrap data frame in SharedData
sd <- SharedData$new(quakes[sample(nrow(quakes), 100),])

# Create a filter input
filter_slider("mag", "Magnitude", sd, column=~mag, step=0.1, width=250)

# Use SharedData like a dataframe with Crosstalk-enabled widgets
bscols(
  leaflet(sd) %>% addTiles() %>% addMarkers(),
  datatable(sd, extensions="Scroller", style="bootstrap", class="compact", width="100%",
    options=list(deferRender=TRUE, scrollY=300, scroller=TRUE))
)

```

Important limitations

Crosstalk has inherent limitations that widget authors and users need to be aware of.

  1. HTML widgets must be specifically modified by their authors to support Crosstalk. Crosstalk cannot magically provide cross-widget interactivity with generic HTML widgets.
  2. Crosstalk currently only works for linked brushing and filtering of views that show individual data points, not aggregate or summary views (where “observations” is defined as a single row in a data frame). For example, histograms are not supported since each bar represents multiple data points; but scatter plot points each represent a single data point, so they are supported.
  3. Because all data must be loaded into the browser, Crosstalk is not appropriate for large data sets. (There’s no hard limit, since HTML widgets require varying amounts of CPU cycles and memory for each data point.)