xterm.d.ts

/**
 * @license MIT
 *
 * This contains the type declarations for the xterm.js library. Note that
 * some interfaces differ between this file and the actual implementation in
 * src/, that's because this file declares the *public* API which is intended
 * to be stable and consumed by external programs.
 */

/// <reference lib="dom"/>

declare module 'xterm' {
  /**
   * A string representing text font weight.
   */
  export type FontWeight = 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900';

  /**
   * A string representing log level.
   */
  export type LogLevel = 'debug' | 'info' | 'warn' | 'error' | 'off';

  /**
   * A string representing a renderer type.
   */
  export type RendererType = 'dom' | 'canvas';

  /**
   * An object containing start up options for the terminal.
   */
  export interface ITerminalOptions {
    /**
     * Whether background should support non-opaque color. It must be set before
     * executing the `Terminal.open()` method and can't be changed later without
     * executing it again. Note that enabling this can negatively impact
     * performance.
     */
    allowTransparency?: boolean;

    /**
     * A data uri of the sound to use for the bell when `bellStyle = 'sound'`.
     */
    bellSound?: string;

    /**
     * The type of the bell notification the terminal will use.
     */
    bellStyle?: 'none' /*| 'visual'*/ | 'sound' /*| 'both'*/;

    /**
     * When enabled the cursor will be set to the beginning of the next line
     * with every new line. This equivalent to sending '\r\n' for each '\n'.
     * Normally the termios settings of the underlying PTY deals with the
     * translation of '\n' to '\r\n' and this setting should not be used. If you
     * deal with data from a non-PTY related source, this settings might be
     * useful.
     */
    convertEol?: boolean;

    /**
     * The number of columns in the terminal.
     */
    cols?: number;

    /**
     * Whether the cursor blinks.
     */
    cursorBlink?: boolean;

    /**
     * The style of the cursor.
     */
    cursorStyle?: 'block' | 'underline' | 'bar';

    /**
     * Whether input should be disabled.
     */
    disableStdin?: boolean;

    /**
     * Whether to draw bold text in bright colors. The default is true.
     */
    drawBoldTextInBrightColors?: boolean;

    /**
     * The font size used to render text.
     */
    fontSize?: number;

    /**
     * The font family used to render text.
     */
    fontFamily?: string;

    /**
     * The font weight used to render non-bold text.
     */
    fontWeight?: FontWeight;

    /**
     * The font weight used to render bold text.
     */
    fontWeightBold?: FontWeight;

    /**
     * The spacing in whole pixels between characters..
     */
    letterSpacing?: number;

    /**
     * The line height used to render text.
     */
    lineHeight?: number;

    /**
     * What log level to use, this will log for all levels below and including
     * what is set:
     *
     * 1. debug
     * 2. info (default)
     * 3. warn
     * 4. error
     * 5. off
     */
    logLevel?: LogLevel;

    /**
     * Whether to treat option as the meta key.
     */
    macOptionIsMeta?: boolean;

    /**
     * Whether holding a modifier key will force normal selection behavior,
     * regardless of whether the terminal is in mouse events mode. This will
     * also prevent mouse events from being emitted by the terminal. For
     * example, this allows you to use xterm.js' regular selection inside tmux
     * with mouse mode enabled.
     */
    macOptionClickForcesSelection?: boolean;

    /**
     * The type of renderer to use, this allows using the fallback DOM renderer
     * when canvas is too slow for the environment. The following features do
     * not work when the DOM renderer is used:
     *
     * - Letter spacing
     * - Cursor blink
     */
    rendererType?: RendererType;

    /**
     * Whether to select the word under the cursor on right click, this is
     * standard behavior in a lot of macOS applications.
     */
    rightClickSelectsWord?: boolean;

    /**
     * The number of rows in the terminal.
     */
    rows?: number;

    /**
     * Whether screen reader support is enabled. When on this will expose
     * supporting elements in the DOM to support NVDA on Windows and VoiceOver
     * on macOS.
     */
    screenReaderMode?: boolean;

    /**
     * The amount of scrollback in the terminal. Scrollback is the amount of
     * rows that are retained when lines are scrolled beyond the initial
     * viewport.
     */
    scrollback?: number;

    /**
     * The size of tab stops in the terminal.
     */
    tabStopWidth?: number;

    /**
     * The color theme of the terminal.
     */
    theme?: ITheme;

    /**
     * Whether "Windows mode" is enabled. Because Windows backends winpty and
     * conpty operate by doing line wrapping on their side, xterm.js does not
     * have access to wrapped lines. When Windows mode is enabled the following
     * changes will be in effect:
     *
     * - Reflow is disabled.
     * - Lines are assumed to be wrapped if the last character of the line is
     *   not whitespace.
     */
    windowsMode?: boolean;

    /**
     * A string containing all characters that are considered word separated by the
     * double click to select work logic.
    */
    wordSeparator?: string;
  }

  /**
   * Contains colors to theme the terminal with.
   */
  export interface ITheme {
    /** The default foreground color */
    foreground?: string,
    /** The default background color */
    background?: string,
    /** The cursor color */
    cursor?: string,
    /** The accent color of the cursor (fg color for a block cursor) */
    cursorAccent?: string,
    /** The selection background color (can be transparent) */
    selection?: string,
    /** ANSI black (eg. `\x1b[30m`) */
    black?: string,
    /** ANSI red (eg. `\x1b[31m`) */
    red?: string,
    /** ANSI green (eg. `\x1b[32m`) */
    green?: string,
    /** ANSI yellow (eg. `\x1b[33m`) */
    yellow?: string,
    /** ANSI blue (eg. `\x1b[34m`) */
    blue?: string,
    /** ANSI magenta (eg. `\x1b[35m`) */
    magenta?: string,
    /** ANSI cyan (eg. `\x1b[36m`) */
    cyan?: string,
    /** ANSI white (eg. `\x1b[37m`) */
    white?: string,
    /** ANSI bright black (eg. `\x1b[1;30m`) */
    brightBlack?: string,
    /** ANSI bright red (eg. `\x1b[1;31m`) */
    brightRed?: string,
    /** ANSI bright green (eg. `\x1b[1;32m`) */
    brightGreen?: string,
    /** ANSI bright yellow (eg. `\x1b[1;33m`) */
    brightYellow?: string,
    /** ANSI bright blue (eg. `\x1b[1;34m`) */
    brightBlue?: string,
    /** ANSI bright magenta (eg. `\x1b[1;35m`) */
    brightMagenta?: string,
    /** ANSI bright cyan (eg. `\x1b[1;36m`) */
    brightCyan?: string,
    /** ANSI bright white (eg. `\x1b[1;37m`) */
    brightWhite?: string
  }

  /**
   * An object containing options for a link matcher.
   */
  export interface ILinkMatcherOptions {
    /**
     * The index of the link from the regex.match(text) call. This defaults to 0
     * (for regular expressions without capture groups).
     */
    matchIndex?: number;

    /**
     * A callback that validates whether to create an individual link, pass
     * whether the link is valid to the callback.
     */
    validationCallback?: (uri: string, callback: (isValid: boolean) => void) => void;

    /**
     * A callback that fires when the mouse hovers over a link for a moment.
     */
    tooltipCallback?: (event: MouseEvent, uri: string) => boolean | void;

    /**
     * A callback that fires when the mouse leaves a link. Note that this can
     * happen even when tooltipCallback hasn't fired for the link yet.
     */
    leaveCallback?: () => void;

    /**
     * The priority of the link matcher, this defines the order in which the
     * link matcher is evaluated relative to others, from highest to lowest. The
     * default value is 0.
     */
    priority?: number;

    /**
     * A callback that fires when the mousedown and click events occur that
     * determines whether a link will be activated upon click. This enables
     * only activating a link when a certain modifier is held down, if not the
     * mouse event will continue propagation (eg. double click to select word).
     */
    willLinkActivate?: (event: MouseEvent, uri: string) => boolean;
  }

  /**
   * An object that can be disposed via a dispose function.
   */
  export interface IDisposable {
    dispose(): void;
  }

  /**
   * An event that can be listened to.
   * @returns an `IDisposable` to stop listening.
   */
  export interface IEvent<T> {
    (listener: (e: T) => any): IDisposable;
  }

  /**
   * Represents a specific line in the terminal that is tracked when scrollback
   * is trimmed and lines are added or removed.
   */
  export interface IMarker extends IDisposable {
    /**
     * A unique identifier for this marker.
     */
    readonly id: number;

    /**
     * Whether this marker is disposed.
     */
    readonly isDisposed: boolean;

    /**
     * The actual line index in the buffer at this point in time.
     */
    readonly line: number;
  }

  /**
   * The set of localizable strings.
   */
  export interface ILocalizableStrings {
    /**
     * The aria label for the underlying input textarea for the terminal.
     */
    promptLabel: string;

    /**
     * Announcement for when line reading is suppressed due to too many lines
     * being printed to the terminal when `screenReaderMode` is enabled.
     */
    tooMuchOutput: string;
  }

  /**
   * The class that represents an xterm.js terminal.
   */
  export class Terminal implements IDisposable {
    /**
     * The element containing the terminal.
     */
    readonly element: HTMLElement;

    /**
     * The textarea that accepts input for the terminal.
     */
    readonly textarea: HTMLTextAreaElement;

    /**
     * The number of rows in the terminal's viewport. Use
     * `ITerminalOptions.rows` to set this in the constructor and
     * `Terminal.resize` for when the terminal exists.
     */
    readonly rows: number;

    /**
     * The number of columns in the terminal's viewport. Use
     * `ITerminalOptions.cols` to set this in the constructor and
     * `Terminal.resize` for when the terminal exists.
     */
    readonly cols: number;

    /**
     * (EXPERIMENTAL) The terminal's current buffer, this might be either the
     * normal buffer or the alt buffer depending on what's running in the
     * terminal.
     */
    readonly buffer: IBuffer;

    /**
     * (EXPERIMENTAL) Get all markers registered against the buffer. If the alt
     * buffer is active this will always return [].
     */
    readonly markers: ReadonlyArray<IMarker>;

    /**
     * Natural language strings that can be localized.
     */
    static strings: ILocalizableStrings;

    /**
     * Creates a new `Terminal` object.
     *
     * @param options An object containing a set of options.
     */
    constructor(options?: ITerminalOptions);

    /**
     * Adds an event listener for the cursor moves.
     * @returns an `IDisposable` to stop listening.
     */
    onCursorMove: IEvent<void>;

    /**
     * Adds an event listener for when a data event fires. This happens for
     * example when the user types or pastes into the terminal. The event value
     * is whatever `string` results, in a typical setup, this should be passed
     * on to the backing pty.
     * @returns an `IDisposable` to stop listening.
     */
    onData: IEvent<string>;

    /**
     * Adds an event listener for a key is pressed. The event value contains the
     * string that will be sent in the data event as well as the DOM event that
     * triggered it.
     * @returns an `IDisposable` to stop listening.
     */
    onKey: IEvent<{ key: string, domEvent: KeyboardEvent }>;

    /**
     * Adds an event listener for when a line feed is added.
     * @returns an `IDisposable` to stop listening.
     */
    onLineFeed: IEvent<void>;

    /**
     * Adds an event listener for when a scroll occurs. The  event value is the
     * new position of the viewport.
     * @returns an `IDisposable` to stop listening.
     */
    onScroll: IEvent<number>;

    /**
     * Adds an event listener for when a selection change occurs.
     * @returns an `IDisposable` to stop listening.
     */
    onSelectionChange: IEvent<void>;

    /**
     * Adds an event listener for when rows are rendered. The event value
     * contains the start row and end rows of the rendered area (ranges from `0`
     * to `Terminal.rows - 1`).
     * @returns an `IDisposable` to stop listening.
     */
    onRender: IEvent<{ start: number, end: number }>;

    /**
     * Adds an event listener for when the terminal is resized. The event value
     * contains the new size.
     * @returns an `IDisposable` to stop listening.
     */
    onResize: IEvent<{ cols: number, rows: number }>;

    /**
     * Adds an event listener for when an OSC 0 or OSC 2 title change occurs.
     * The event value is the new title.
     * @returns an `IDisposable` to stop listening.
     */
    onTitleChange: IEvent<string>;

    /**
     * Unfocus the terminal.
     */
    blur(): void;

    /**
     * Focus the terminal.
     */
    focus(): void;

    /**
     * Resizes the terminal. It's best practice to debounce calls to resize,
     * this will help ensure that the pty can respond to the resize event
     * before another one occurs.
     * @param x The number of columns to resize to.
     * @param y The number of rows to resize to.
     */
    resize(columns: number, rows: number): void;

    /**
     * Opens the terminal within an element.
     * @param parent The element to create the terminal within. This element
     * must be visible (have dimensions) when `open` is called as several DOM-
     * based measurements need to be performed when this function is called.
     */
    open(parent: HTMLElement): void;

    /**
     * Attaches a custom key event handler which is run before keys are
     * processed, giving consumers of xterm.js ultimate control as to what keys
     * should be processed by the terminal and what keys should not.
     * @param customKeyEventHandler The custom KeyboardEvent handler to attach.
     * This is a function that takes a KeyboardEvent, allowing consumers to stop
     * propagation and/or prevent the default action. The function returns
     * whether the event should be processed by xterm.js.
     */
    attachCustomKeyEventHandler(customKeyEventHandler: (event: KeyboardEvent) => boolean): void;

    /**
     * (EXPERIMENTAL) Adds a handler for CSI escape sequences.
     * @param flag The flag should be one-character string, which specifies the
     * final character (e.g "m" for SGR) of the CSI sequence.
     * @param callback The function to handle the escape sequence. The callback
     * is called with the numerical params, as well as the special characters
     * (e.g. "$" for DECSCPP). If the sequence has subparams the array will
     * contain subarrays with their numercial values.
     * Return true if the sequence was handled; false if
     * we should try a previous handler (set by addCsiHandler or setCsiHandler).
     * The most recently-added handler is tried first.
     * @return An IDisposable you can call to remove this handler.
     */
    addCsiHandler(flag: string, callback: (params: (number | number[])[], collect: string) => boolean): IDisposable;

    /**
     * (EXPERIMENTAL) Adds a handler for OSC escape sequences.
     * @param ident The number (first parameter) of the sequence.
     * @param callback The function to handle the escape sequence. The callback
     * is called with OSC data string. Return true if the sequence was handled;
     * false if we should try a previous handler (set by addOscHandler or
     * setOscHandler). The most recently-added handler is tried first.
     * @return An IDisposable you can call to remove this handler.
     */
    addOscHandler(ident: number, callback: (data: string) => boolean): IDisposable;

    /**
     * (EXPERIMENTAL) Registers a link matcher, allowing custom link patterns to
     * be matched and handled.
     * @param regex The regular expression to search for, specifically this
     * searches the textContent of the rows. You will want to use \s to match a
     * space ' ' character for example.
     * @param handler The callback when the link is called.
     * @param options Options for the link matcher.
     * @return The ID of the new matcher, this can be used to deregister.
     */
    registerLinkMatcher(regex: RegExp, handler: (event: MouseEvent, uri: string) => void, options?: ILinkMatcherOptions): number;

    /**
     * (EXPERIMENTAL) Deregisters a link matcher if it has been registered.
     * @param matcherId The link matcher's ID (returned after register)
     */
    deregisterLinkMatcher(matcherId: number): void;

    /**
     * (EXPERIMENTAL) Registers a character joiner, allowing custom sequences of
     * characters to be rendered as a single unit. This is useful in particular
     * for rendering ligatures and graphemes, among other things.
     *
     * Each registered character joiner is called with a string of text
     * representing a portion of a line in the terminal that can be rendered as
     * a single unit. The joiner must return a sorted array, where each entry is
     * itself an array of length two, containing the start (inclusive) and end
     * (exclusive) index of a substring of the input that should be rendered as
     * a single unit. When multiple joiners are provided, the results of each
     * are collected. If there are any overlapping substrings between them, they
     * are combined into one larger unit that is drawn together.
     *
     * All character joiners that are registered get called every time a line is
     * rendered in the terminal, so it is essential for the handler function to
     * run as quickly as possible to avoid slowdowns when rendering. Similarly,
     * joiners should strive to return the smallest possible substrings to
     * render together, since they aren't drawn as optimally as individual
     * characters.
     *
     * NOTE: character joiners are only used by the canvas renderer.
     *
     * @param handler The function that determines character joins. It is called
     * with a string of text that is eligible for joining and returns an array
     * where each entry is an array containing the start (inclusive) and end
     * (exclusive) indexes of ranges that should be rendered as a single unit.
     * @return The ID of the new joiner, this can be used to deregister
     */
    registerCharacterJoiner(handler: (text: string) => [number, number][]): number;

    /**
     * (EXPERIMENTAL) Deregisters the character joiner if one was registered.
     * NOTE: character joiners are only used by the canvas renderer.
     * @param joinerId The character joiner's ID (returned after register)
     */
    deregisterCharacterJoiner(joinerId: number): void;

    /**
     * (EXPERIMENTAL) Adds a marker to the normal buffer and returns it. If the
     * alt buffer is active, undefined is returned.
     * @param cursorYOffset The y position offset of the marker from the cursor.
     */
    addMarker(cursorYOffset: number): IMarker;

    /**
     * Gets whether the terminal has an active selection.
     */
    hasSelection(): boolean;

    /**
     * Gets the terminal's current selection, this is useful for implementing
     * copy behavior outside of xterm.js.
     */
    getSelection(): string;

    /**
     * Gets the selection position or undefined if there is no selection.
     */
    getSelectionPosition(): ISelectionPosition | undefined;

    /**
     * Clears the current terminal selection.
     */
    clearSelection(): void;

    /**
     * Selects text within the terminal.
     * @param column The column the selection starts at..
     * @param row The row the selection starts at.
     * @param length The length of the selection.
     */
    select(column: number, row: number, length: number): void;

    /**
     * Selects all text within the terminal.
     */
    selectAll(): void;

    /**
     * Selects text in the buffer between 2 lines.
     * @param start The 0-based line index to select from (inclusive).
     * @param end The 0-based line index to select to (inclusive).
     */
    selectLines(start: number, end: number): void;

    /*
     * Disposes of the terminal, detaching it from the DOM and removing any
     * active listeners.
     */
    dispose(): void;

    /**
     * Scroll the display of the terminal
     * @param amount The number of lines to scroll down (negative scroll up).
     */
    scrollLines(amount: number): void;

    /**
     * Scroll the display of the terminal by a number of pages.
     * @param pageCount The number of pages to scroll (negative scrolls up).
     */
    scrollPages(pageCount: number): void;

    /**
     * Scrolls the display of the terminal to the top.
     */
    scrollToTop(): void;

    /**
     * Scrolls the display of the terminal to the bottom.
     */
    scrollToBottom(): void;

    /**
     * Scrolls to a line within the buffer.
     * @param line The 0-based line index to scroll to.
     */
    scrollToLine(line: number): void;

    /**
     * Clear the entire buffer, making the prompt line the new first line.
     */
    clear(): void;

    /**
     * Writes text to the terminal.
     * @param data The text to write to the terminal.
     */
    write(data: string): void;

    /**
     * Writes text to the terminal, followed by a break line character (\n).
     * @param data The text to write to the terminal.
     */
    writeln(data: string): void;

    /**
     * Writes UTF8 data to the terminal. This has a slight performance advantage
     * over the string based write method due to lesser data conversions needed
     * on the way from the pty to xterm.js.
     * @param data The data to write to the terminal.
     */
    writeUtf8(data: Uint8Array): void;

    /**
     * Retrieves an option's value from the terminal.
     * @param key The option key.
     */
    getOption(key: 'bellSound' | 'bellStyle' | 'cursorStyle' | 'fontFamily' | 'fontWeight' | 'fontWeightBold' | 'logLevel' | 'rendererType' | 'termName' | 'wordSeparator'): string;
    /**
     * Retrieves an option's value from the terminal.
     * @param key The option key.
     */
    getOption(key: 'allowTransparency' | 'cancelEvents' | 'convertEol' | 'cursorBlink' | 'disableStdin' | 'macOptionIsMeta' | 'rightClickSelectsWord' | 'popOnBell' | 'screenKeys' | 'useFlowControl' | 'visualBell' | 'windowsMode'): boolean;
    /**
     * Retrieves an option's value from the terminal.
     * @param key The option key.
     */
    getOption(key: 'colors'): string[];
    /**
     * Retrieves an option's value from the terminal.
     * @param key The option key.
     */
    getOption(key: 'cols' | 'fontSize' | 'letterSpacing' | 'lineHeight' | 'rows' | 'tabStopWidth' | 'scrollback'): number;
    /**
     * Retrieves an option's value from the terminal.
     * @param key The option key.
     */
    getOption(key: 'handler'): (data: string) => void;
    /**
     * Retrieves an option's value from the terminal.
     * @param key The option key.
     */
    getOption(key: string): any;

    /**
     * Sets an option on the terminal.
     * @param key The option key.
     * @param value The option value.
     */
    setOption(key: 'fontFamily' | 'termName' | 'bellSound' | 'wordSeparator', value: string): void;
    /**
    * Sets an option on the terminal.
    * @param key The option key.
    * @param value The option value.
    */
    setOption(key: 'fontWeight' | 'fontWeightBold', value: null | 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900'): void;
    /**
    * Sets an option on the terminal.
    * @param key The option key.
    * @param value The option value.
    */
    setOption(key: 'logLevel', value: LogLevel): void;
    /**
     * Sets an option on the terminal.
     * @param key The option key.
     * @param value The option value.
     */
    setOption(key: 'bellStyle', value: null | 'none' | 'visual' | 'sound' | 'both'): void;
    /**
     * Sets an option on the terminal.
     * @param key The option key.
     * @param value The option value.
     */
    setOption(key: 'cursorStyle', value: null | 'block' | 'underline' | 'bar'): void;
    /**
     * Sets an option on the terminal.
     * @param key The option key.
     * @param value The option value.
     */
    setOption(key: 'allowTransparency' | 'cancelEvents' | 'convertEol' | 'cursorBlink' | 'disableStdin' | 'macOptionIsMeta' | 'popOnBell' | 'rightClickSelectsWord' | 'screenKeys' | 'useFlowControl' | 'visualBell' | 'windowsMode', value: boolean): void;
    /**
     * Sets an option on the terminal.
     * @param key The option key.
     * @param value The option value.
     */
    setOption(key: 'colors', value: string[]): void;
    /**
     * Sets an option on the terminal.
     * @param key The option key.
     * @param value The option value.
     */
    setOption(key: 'fontSize' | 'letterSpacing' | 'lineHeight' | 'tabStopWidth' | 'scrollback', value: number): void;
    /**
     * Sets an option on the terminal.
     * @param key The option key.
     * @param value The option value.
     */
    setOption(key: 'handler', value: (data: string) => void): void;
    /**
     * Sets an option on the terminal.
     * @param key The option key.
     * @param value The option value.
     */
    setOption(key: 'theme', value: ITheme): void;
    /**
     * Sets an option on the terminal.
     * @param key The option key.
     * @param value The option value.
     */
    setOption(key: 'cols' | 'rows', value: number): void;
    /**
     * Sets an option on the terminal.
     * @param key The option key.
     * @param value The option value.
     */
    setOption(key: string, value: any): void;

    /**
     * Tells the renderer to refresh terminal content between two rows
     * (inclusive) at the next opportunity.
     * @param start The row to start from (between 0 and this.rows - 1).
     * @param end The row to end at (between start and this.rows - 1).
     */
    refresh(start: number, end: number): void;

    /**
     * Perform a full reset (RIS, aka '\x1bc').
     */
    reset(): void

    /**
     * Applies an addon to the Terminal prototype, making it available to all
     * newly created Terminals.
     * @param addon The addon to apply.
     * @deprecated Use the new loadAddon API/addon format.
     */
    static applyAddon(addon: any): void;

    /**
     * (EXPERIMENTAL) Loads an addon into this instance of xterm.js.
     * @param addon The addon to load.
     */
    loadAddon(addon: ITerminalAddon): void;
  }

  /**
   * An addon that can provide additional functionality to the terminal.
   */
  export interface ITerminalAddon extends IDisposable {
    /**
     * (EXPERIMENTAL) This is called when the addon is activated.
     */
    activate(terminal: Terminal): void;
  }

  /**
   * An object representing a selection within the terminal.
   */
  interface ISelectionPosition {
    /**
     * The start column of the selection.
     */
    startColumn: number;

    /**
     * The start row of the selection.
     */
    startRow: number;

    /**
     * The end column of the selection.
     */
    endColumn: number;

    /**
     * The end row of the selection.
     */
    endRow: number;
  }

  /**
   * Represents a terminal buffer.
   */
  interface IBuffer {
    /**
     * The y position of the cursor. This ranges between `0` (when the
     * cursor is at baseY) and `Terminal.rows - 1` (when the cursor is on the
     * last row).
     */
    readonly cursorY: number;

    /**
     * The x position of the cursor. This ranges between `0` (left side) and
     * `Terminal.cols - 1` (right side).
     */
    readonly cursorX: number;

    /**
     * The line within the buffer where the top of the viewport is.
     */
    readonly viewportY: number;

    /**
     * The line within the buffer where the top of the bottom page is (when
     * fully scrolled down);
     */
    readonly baseY: number;

    /**
     * The amount of lines in the buffer.
     */
    readonly length: number;

    /**
     * Gets a line from the buffer, or undefined if the line index does not
     * exist.
     *
     * Note that the result of this function should be used immediately after
     * calling as when the terminal updates it could lead to unexpected
     * behavior.
     *
     * @param y The line index to get.
     */
    getLine(y: number): IBufferLine | undefined;
  }

  /**
   * Represents a line in the terminal's buffer.
   */
  interface IBufferLine {
    /**
     * Whether the line is wrapped from the previous line.
     */
    readonly isWrapped: boolean;

    /**
     * Gets a cell from the line, or undefined if the line index does not exist.
     *
     * Note that the result of this function should be used immediately after
     * calling as when the terminal updates it could lead to unexpected
     * behavior.
     *
     * @param x The character index to get.
     */
    getCell(x: number): IBufferCell | undefined;

    /**
     * Gets the line as a string. Note that this is gets only the string for the
     * line, not taking isWrapped into account.
     *
     * @param trimRight Whether to trim any whitespace at the right of the line.
     * @param startColumn The column to start from (inclusive).
     * @param endColumn The column to end at (exclusive).
     */
    translateToString(trimRight?: boolean, startColumn?: number, endColumn?: number): string;
  }

  /**
   * Represents a single cell in the terminal's buffer.
   */
  interface IBufferCell {
    /**
     * The character within the cell.
     */
    readonly char: string;

    /**
     * The width of the character. Some examples:
     *
     * - This is `1` for most cells.
     * - This is `2` for wide character like CJK glyphs.
     * - This is `0` for cells immediately following cells with a width of `2`.
     */
    readonly width: number;
  }
}