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WriteStream

class WriteStream
extends net.Socket

Represents the writable side of a TTY. In normal circumstances, process.stdout and process.stderr will be the onlytty.WriteStream instances created for a Node.js process and there should be no reason to create additional instances.

Constructors Jump to heading

new
Jump to headingWriteStream(fd: number)

Properties Jump to heading

A number specifying the number of columns the TTY currently has. This property is updated whenever the 'resize' event is emitted.

A boolean that is always true.

A number specifying the number of rows the TTY currently has. This property is updated whenever the 'resize' event is emitted.

Jump to headingaddListener(
event: string,
listener: (...args: any[]) => void,
): this
Jump to headingaddListener(
event: "resize",
listener: () => void,
): this
Jump to headingclearLine(
dir: Direction,
callback?: () => void,
): boolean

writeStream.clearLine() clears the current line of this WriteStream in a direction identified by dir.

Jump to headingclearScreenDown(callback?: () => void): boolean

writeStream.clearScreenDown() clears this WriteStream from the current cursor down.

Jump to headingcursorTo(
x: number,
y?: number,
callback?: () => void,
): boolean

writeStream.cursorTo() moves this WriteStream's cursor to the specified position.

Jump to headingcursorTo(
x: number,
callback: () => void,
): boolean
Jump to headingemit(
event: string | symbol,
...args: any[],
): boolean
Jump to headingemit(event: "resize"): boolean
Jump to headinggetColorDepth(env?: object): number

Returns:

  • 1 for 2,
  • 4 for 16,
  • 8 for 256,
  • 24 for 16,777,216 colors supported.

Use this to determine what colors the terminal supports. Due to the nature of colors in terminals it is possible to either have false positives or false negatives. It depends on process information and the environment variables that may lie about what terminal is used. It is possible to pass in an env object to simulate the usage of a specific terminal. This can be useful to check how specific environment settings behave.

To enforce a specific color support, use one of the below environment settings.

  • 2 colors: FORCE_COLOR = 0 (Disables colors)
  • 16 colors: FORCE_COLOR = 1
  • 256 colors: FORCE_COLOR = 2
  • 16,777,216 colors: FORCE_COLOR = 3

Disabling color support is also possible by using the NO_COLOR and NODE_DISABLE_COLORS environment variables.

Jump to headinggetWindowSize(): [number, number]

writeStream.getWindowSize() returns the size of the TTY corresponding to this WriteStream. The array is of the type [numColumns, numRows] where numColumns and numRows represent the number of columns and rows in the corresponding TTY.

Jump to headinghasColors(count?: number): boolean

Returns true if the writeStream supports at least as many colors as provided in count. Minimum support is 2 (black and white).

This has the same false positives and negatives as described in writeStream.getColorDepth().

process.stdout.hasColors();
// Returns true or false depending on if `stdout` supports at least 16 colors.
process.stdout.hasColors(256);
// Returns true or false depending on if `stdout` supports at least 256 colors.
process.stdout.hasColors({ TMUX: '1' });
// Returns true.
process.stdout.hasColors(2 ** 24, { TMUX: '1' });
// Returns false (the environment setting pretends to support 2 ** 8 colors).
Jump to headinghasColors(env?: object): boolean
Jump to headinghasColors(
count: number,
env?: object,
): boolean
Jump to headingmoveCursor(
dx: number,
dy: number,
callback?: () => void,
): boolean

writeStream.moveCursor() moves this WriteStream's cursor relative to its current position.

Jump to headingon(
event: string,
listener: (...args: any[]) => void,
): this
Jump to headingon(
event: "resize",
listener: () => void,
): this
Jump to headingonce(
event: string,
listener: (...args: any[]) => void,
): this
Jump to headingonce(
event: "resize",
listener: () => void,
): this
Jump to headingprependListener(
event: string,
listener: (...args: any[]) => void,
): this
Jump to headingprependListener(
event: "resize",
listener: () => void,
): this
Jump to headingprependOnceListener(
event: string,
listener: (...args: any[]) => void,
): this
Jump to headingprependOnceListener(
event: "resize",
listener: () => void,
): this
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