Custom Rendering

You may want to customize how your data is displayed beyond what the built-in formatters provide. For example, inserting a link, combining data from multiple columns, or showing a column total that updates on filtering.

In reactable, you can customize data rendering using either an R or JavaScript function that returns custom content:

R render functions	JavaScript render functions
reactable(iris, columns = list( Species = colDef( cell = function(value) { htmltools::tags$b(value) } ) ))	reactable(iris, columns = list( Species = colDef( cell = JS("function(cellInfo) { return `<b>${cellInfo.value}</b>' }") ) ))
Easier to use but more static Render once, when the table is created Supports htmltools and htmlwidgets	Harder to use but more dynamic Render on the fly, based on client-side state Can be more efficient in large tables

Whichever one to use depends on the situation and personal preference. You might prefer to use R render functions except in cases where you need more dynamic behavior (e.g., render based on filtered state) or have a very large table.

Example: column total with filtering

This example requires reactable v0.3.0 or above.

For example, you can easily add a column total using an R render function:

data <- MASS::Cars93[20:24, c("Manufacturer", "Model", "Type", "Price")]

reactable(
  data,
  searchable = TRUE,
  columns = list(
    Price = colDef(footer = function(values) {
      htmltools::tags$b(sprintf("$%.2f", sum(values)))
    }),
    Manufacturer = colDef(footer = htmltools::tags$b("Total"))
  )
)

However, the column total doesn’t update with filtering. For that, you need a JavaScript render function with access to the client-side filtered state:

data <- MASS::Cars93[20:24, c("Manufacturer", "Model", "Type", "Price")]

reactable(
  data,
  searchable = TRUE,
  columns = list(
    Price = colDef(
      html = TRUE,
      footer = JS("function(column, state) {
        let total = 0
        state.sortedData.forEach(function(row) {
          total += row[column.id]
        })
        return '<b>$' + total.toFixed(2) + '</b>'
      }")
    ),
    Manufacturer = colDef(html = TRUE, footer = "<b>Total</b>")
  )
)

Cells

R render function

To customize cell rendering, provide an R function with up to 3 optional arguments:

colDef(
  cell = function(value, index, name) {
    # input:
    #   - value, the cell value
    #   - index, the row index (optional)
    #   - name, the column name (optional)
    #
    # output:
    #   - content to render (e.g. an HTML tag or widget)
    htmltools::div(style = "color: red", toupper(value))
  }
)

JavaScript render function

Or a JavaScript function, wrapped in JS(), with up to 2 optional arguments:

colDef(
  cell = JS("
    function(cellInfo, state) {
      // input:
      //  - cellInfo, an object containing cell info
      //  - state, an object containing the table state (optional)
      //
      // output:
      //  - content to render (e.g. an HTML string)
      return `<div>${cellInfo.value}</div>`
    }
  "),
  html = TRUE  # to render as HTML
)

With JavaScript functions, you can also customize rendering of grouped cells and aggregated cells:

colDef(
  grouped = JS("function(cellInfo, state) {
    return cellInfo.value
  }"),
  aggregated = JS("function(cellInfo, state) {
    return cellInfo.value
  }")
)

cellInfo properties

Property	Example	Description
value	"setosa"	cell value
row	{ Petal.Length: 1.7, Species: "setosa" }	row data
column	{ id: "Petal.Length" }	column info object
index	20	row index (zero-based)
viewIndex	0	row index within the page (zero-based)
aggregated	true	whether the row is aggregated
expanded	true	whether the row is expanded
filterValue	"petal"	column filter value
subRows	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	sub rows data (aggregated cells only)
level	0	row nesting depth (zero-based)
selected	true	whether the row is selected

state properties

Property	Example	Description
sorted	[{ id: "Petal.Length", desc: true }, ...]	columns being sorted in the table
page	2	page index (zero-based)
pageSize	10	page size
pages	5	number of pages
filters	[{ id: "Species", value: "petal" }]	column filter values
searchValue	"petal"	table search value
selected	[0, 1, 4]	selected row indices (zero-based)
pageRows	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	current row data on the page
sortedData	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	current row data in the table (after sorting, filtering, grouping)
data	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	original row data in the table
meta	{ custom: 123 }	custom table metadata from reactable() (new in v0.4.0)
hiddenColumns	["Petal.Length"]	columns being hidden in the table

Headers

R render function

To customize header rendering, provide an R function with up to 2 optional arguments:

colDef(
  header = function(value, name) {
    # input:
    #   - value, the header value
    #   - name, the column name (optional)
    #
    # output:
    #   - content to render (e.g. an HTML tag or widget)
    htmltools::div(value)
  }
)

JavaScript render function

Or a JavaScript function with up to 2 optional arguments:

colDef(
  header = JS("
    function(column, state) {
      // input:
      //  - column, an object containing column properties
      //  - state, an object containing the table state (optional)
      //
      // output:
      //  - content to render (e.g. an HTML string)
      return `<div>${column.name}</div>`
    }
  "),
  html = TRUE  # to render as HTML
)

column properties

Property	Example	Description
id	"Petal.Length"	column ID
name	"Petal Length"	column display name
filterValue	"petal"	column filter value
setFilter	function setFilter(value: any)	function to set the column filter value (set to undefined to clear the filter)
column	{ id: "Petal.Length", name: "Petal Length", filterValue: "petal" }	column info object (deprecated in v0.3.0)
data	[{ Petal.Length: 1.7, Petal.Width: 0.2, _subRows: [] }, ...]	current row data in the table (deprecated in v0.3.0)

state properties

Property	Example	Description
sorted	[{ id: "Petal.Length", desc: true }, ...]	columns being sorted in the table
page	2	page index (zero-based)
pageSize	10	page size
pages	5	number of pages
filters	[{ id: "Species", value: "petal" }]	column filter values
searchValue	"petal"	table search value
selected	[0, 1, 4]	selected row indices (zero-based)
pageRows	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	current row data on the page
sortedData	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	current row data in the table (after sorting, filtering, grouping)
data	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	original row data in the table
meta	{ custom: 123 }	custom table metadata from reactable() (new in v0.4.0)
hiddenColumns	["Petal.Length"]	columns being hidden in the table

Footers

R render function

To add footer content, provide an R function with up to 2 optional arguments:

colDef(
  footer = function(values, name) {
    # input:
    #   - values, the column values
    #   - name, the column name (optional)
    #
    # output:
    #   - content to render (e.g. an HTML tag or widget)
    htmltools::div(paste("Total:", sum(values)))
  }
)

JavaScript render function

Or a JavaScript function with up to 2 optional arguments:

colDef(
  footer = JS("
    function(column, state) {
      // input:
      //  - column, an object containing column properties
      //  - state, an object containing the table state (optional)
      //
      // output:
      //  - content to render (e.g. an HTML string)
      return `<div>Rows: ${state.sortedData.length}</div>`
    }
  "),
  html = TRUE  # to render as HTML
)

column properties

Property	Example	Description
id	"Petal.Length"	column ID
name	"Petal Length"	column display name
filterValue	"petal"	column filter value
setFilter	function setFilter(value: any)	function to set the column filter value (set to undefined to clear the filter)
column	{ id: "Petal.Length", name: "Petal Length", filterValue: "petal" }	column info object (deprecated in v0.3.0)
data	[{ Petal.Length: 1.7, Petal.Width: 0.2, _subRows: [] }, ...]	current row data in the table (deprecated in v0.3.0)

state properties

Property	Example	Description
sorted	[{ id: "Petal.Length", desc: true }, ...]	columns being sorted in the table
page	2	page index (zero-based)
pageSize	10	page size
pages	5	number of pages
filters	[{ id: "Species", value: "petal" }]	column filter values
searchValue	"petal"	table search value
selected	[0, 1, 4]	selected row indices (zero-based)
pageRows	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	current row data on the page
sortedData	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	current row data in the table (after sorting, filtering, grouping)
data	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	original row data in the table
meta	{ custom: 123 }	custom table metadata from reactable() (new in v0.4.0)
hiddenColumns	["Petal.Length"]	columns being hidden in the table

Expandable Row Details

R render function

To add expandable row details, provide an R function with up to 2 optional arguments:

reactable(
  details = function(index, name) {
    # input:
    #   - index, the row index
    #   - name, the column name (optional)
    #
    # output:
    #   - content to render (e.g., an HTML tag or nested table), or NULL to hide details
    htmltools::div(
      paste("Details for row:", index),
      reactable(data[index, ])
    )
  }
)

JavaScript render function

Or a JavaScript function with up to 2 optional arguments:

reactable(
  details = JS("
    function(rowInfo, state) {
      // input:
      //  - rowInfo, an object containing row info
      //  - state, an object containing the table state (optional)
      //
      // output:
      //  - content to render (e.g. an HTML string)
      return `<div>Details for row: ${rowInfo.index}</div>`
    }
  ")
)

rowInfo properties

Property	Example	Description
values	{ Petal.Length: 1.7, Species: "setosa" }	row data values
row	{ Petal.Length: 1.7, Species: "setosa" }	same as values (deprecated in v0.3.0)
index	20	row index (zero-based)
viewIndex	0	row index within the page (zero-based)
expanded	true	whether the row is expanded
level	0	row nesting depth (zero-based)
selected	true	whether the row is selected

state properties

Property	Example	Description
sorted	[{ id: "Petal.Length", desc: true }, ...]	columns being sorted in the table
page	2	page index (zero-based)
pageSize	10	page size
pages	5	number of pages
filters	[{ id: "Species", value: "petal" }]	column filter values
searchValue	"petal"	table search value
selected	[0, 1, 4]	selected row indices (zero-based)
pageRows	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	current row data on the page
sortedData	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	current row data in the table (after sorting, filtering, grouping)
data	[{ Petal.Length: 1.7, Species: "setosa" }, ...]	original row data in the table
meta	{ custom: 123 }	custom table metadata from reactable() (new in v0.4.0)
hiddenColumns	["Petal.Length"]	columns being hidden in the table