nstdlib-nightly/lib/internal/readline/callbacks.mjs

Node.js standard library converted to runtime-agnostic ES modules.

// Source: https://github.com/nodejs/node/blob/65eff1eb/lib/internal/readline/callbacks.js

import { codes as __codes__ } from "nstdlib/lib/internal/errors";
import { validateFunction } from "nstdlib/lib/internal/validators";
import { CSI } from "nstdlib/lib/internal/readline/utils";

const { ERR_INVALID_ARG_VALUE, ERR_INVALID_CURSOR_POS } = __codes__;

const { kClearLine, kClearScreenDown, kClearToLineBeginning, kClearToLineEnd } =
  CSI;

/**
 * moves the cursor to the x and y coordinate on the given stream
 */

function cursorTo(stream, x, y, callback) {
  if (callback !== undefined) {
    validateFunction(callback, "callback");
  }

  if (typeof y === "function") {
    callback = y;
    y = undefined;
  }

  if (Number.isNaN(x)) throw new ERR_INVALID_ARG_VALUE("x", x);
  if (Number.isNaN(y)) throw new ERR_INVALID_ARG_VALUE("y", y);

  if (stream == null || (typeof x !== "number" && typeof y !== "number")) {
    if (typeof callback === "function") process.nextTick(callback, null);
    return true;
  }

  if (typeof x !== "number") throw new ERR_INVALID_CURSOR_POS();

  const data = typeof y !== "number" ? CSI`${x + 1}G` : CSI`${y + 1};${x + 1}H`;
  return stream.write(data, callback);
}

/**
 * moves the cursor relative to its current location
 */

function moveCursor(stream, dx, dy, callback) {
  if (callback !== undefined) {
    validateFunction(callback, "callback");
  }

  if (stream == null || !(dx || dy)) {
    if (typeof callback === "function") process.nextTick(callback, null);
    return true;
  }

  let data = "";

  if (dx < 0) {
    data += CSI`${-dx}D`;
  } else if (dx > 0) {
    data += CSI`${dx}C`;
  }

  if (dy < 0) {
    data += CSI`${-dy}A`;
  } else if (dy > 0) {
    data += CSI`${dy}B`;
  }

  return stream.write(data, callback);
}

/**
 * clears the current line the cursor is on:
 *   -1 for left of the cursor
 *   +1 for right of the cursor
 *    0 for the entire line
 */

function clearLine(stream, dir, callback) {
  if (callback !== undefined) {
    validateFunction(callback, "callback");
  }

  if (stream === null || stream === undefined) {
    if (typeof callback === "function") process.nextTick(callback, null);
    return true;
  }

  const type =
    dir < 0 ? kClearToLineBeginning : dir > 0 ? kClearToLineEnd : kClearLine;
  return stream.write(type, callback);
}

/**
 * clears the screen from the current position of the cursor down
 */

function clearScreenDown(stream, callback) {
  if (callback !== undefined) {
    validateFunction(callback, "callback");
  }

  if (stream === null || stream === undefined) {
    if (typeof callback === "function") process.nextTick(callback, null);
    return true;
  }

  return stream.write(kClearScreenDown, callback);
}

export { clearLine };
export { clearScreenDown };
export { cursorTo };
export { moveCursor };