Class: Console
WebR.Console
Text-based Interactive Console for WebR
A helper application to assist in creating an interactive R REPL based on JavaScript callbacks.
Callback functions stdout and stderr are called with a single line of output as the first argument. The default implementation of stdout and stderr writes to the console using console.log and console.error.
R code can be sent as input by calling the stdin method with a single line of textual input.
A long running R computation can be interrupted by calling the interrupt method.
The prompt callback function is called when webR produces a prompt at the REPL console and is therefore awaiting user input. The prompt character (usually > or +) is given as the first argument to the callback function. The default implementation of prompt shows a JavaScript prompt asking the user for input, and then sends the user input to stdin.
The canvasImage callback function is called when webR writes plots to the built-in HTML canvas graphics device.
The canvasNewPage callback function is called when webR creates a new plot.
Once constructed, start the Console using the run method. The run method starts an asynchronous infinite loop that waits for output from the webR worker and then calls the relevant callbacks.
Table of contents
Constructors
Properties
Methods
Constructors
constructor
• new Console(callbacks?, options?): Console
Parameters
| Name | Type | Description |
|---|---|---|
callbacks |
ConsoleCallbacks |
A list of webR Console callbacks to be used for this console. |
options |
WebROptions |
The options to use for the new instance of webR started to support this console. |
Returns
Defined in
webR/console.ts:71
Properties
canvas
• canvas: undefined | HTMLCanvasElement
A HTML canvas element
The canvas graphics device writes to this element by default. Undefined when HTML canvas is unsupported.
Defined in
webR/console.ts:53
webR
• webR: WebR
The supporting instance of webR
Defined in
webR/console.ts:46
Methods
interrupt
▸ interrupt(): void
Interrupt a long running R computation and return to the prompt
Returns
void
Defined in
webR/console.ts:106
run
▸ run(): void
Start the webR console
Returns
void
Defined in
webR/console.ts:159
stdin
▸ stdin(input): void
Write a line of input to webR’s REPL through stdin
Parameters
| Name | Type | Description |
|---|---|---|
input |
string |
A line of input text. |
Returns
void
Defined in
webR/console.ts:99