R: Delay Rendering for an Expression

render_delayed {rmarkdown} | R Documentation

## Delay Rendering for an Expression

### Description

In a Shiny document, evaluate the given expression after the document has finished rendering, instead of during render.

### Usage

    render_delayed(expr)

### Arguments

`expr` | The expression to evaluate.

### Details

This function is useful inside Shiny documents. It delays the evaluation of its argument until the document has finished its initial render, so that the document can be viewed before the calculation is finished.

Any expression that returns HTML can be wrapped in `render_delayed`.

### Value

An object representing the expression.

### Note

`expr` is evaluated in a copy of the environment in which the `render_delayed` call appears. Consequently, no side effects created by `expr` are visible in succeeding expressions, nor are changes to the environment after the call to `render_delayed` visible to `expr`.

`expr` must be an expression that produces HTML.

### Examples

    ## Not run:

    # Add the following code to an R Markdown document

    div(Sys.time())

    render_delayed({
     Sys.sleep(3)      # simulate an expensive computation
     div(Sys.time())
    })

    div(Sys.time())

    ## End(Not run)

[Package rmarkdown version 1.6 Index]