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// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
// Inspiration for this code comes from Salvatore Sanfilippo's linenoise.
// https://github.com/antirez/linenoise
// Reference:
// * http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
// * http://www.3waylabs.com/nw/WWW/products/wizcon/vt220.html
'use strict';
const errors = require('internal/errors');
const { debug, inherits } = require('util');
const { Buffer } = require('buffer');
const EventEmitter = require('events');
const { StringDecoder } = require('string_decoder');
const {
CSI,
emitKeys,
getStringWidth,
isFullWidthCodePoint,
stripVTControlCharacters
} = require('internal/readline');
const {
kEscape,
kClearToBeginning,
kClearToEnd,
kClearLine,
kClearScreenDown
} = CSI;
const now = process.binding('timer_wrap').Timer.now;
const kHistorySize = 30;
const kMincrlfDelay = 100;
// \r\n, \n, or \r followed by something other than \n
const lineEnding = /\r?\n|\r(?!\n)/;
const KEYPRESS_DECODER = Symbol('keypress-decoder');
const ESCAPE_DECODER = Symbol('escape-decoder');
// GNU readline library - keyseq-timeout is 500ms (default)
const ESCAPE_CODE_TIMEOUT = 500;
function createInterface(input, output, completer, terminal) {
return new Interface(input, output, completer, terminal);
}
function Interface(input, output, completer, terminal) {
if (!(this instanceof Interface)) {
return new Interface(input, output, completer, terminal);
}
this._sawReturnAt = 0;
this.isCompletionEnabled = true;
this._sawKeyPress = false;
this._previousKey = null;
EventEmitter.call(this);
var historySize;
var removeHistoryDuplicates = false;
let crlfDelay;
let prompt = '> ';
if (input && input.input) {
// an options object was given
output = input.output;
completer = input.completer;
terminal = input.terminal;
historySize = input.historySize;
removeHistoryDuplicates = input.removeHistoryDuplicates;
if (input.prompt !== undefined) {
prompt = input.prompt;
}
crlfDelay = input.crlfDelay;
input = input.input;
}
if (completer && typeof completer !== 'function') {
throw new errors.TypeError('ERR_INVALID_OPT_VALUE', 'completer', completer);
}
if (historySize === undefined) {
historySize = kHistorySize;
}
if (typeof historySize !== 'number' ||
isNaN(historySize) ||
historySize < 0) {
throw new errors.RangeError(
'ERR_INVALID_OPT_VALUE',
'historySize',
historySize
);
}
// backwards compat; check the isTTY prop of the output stream
// when `terminal` was not specified
if (terminal === undefined && !(output === null || output === undefined)) {
terminal = !!output.isTTY;
}
var self = this;
this.output = output;
this.input = input;
this.historySize = historySize;
this.removeHistoryDuplicates = !!removeHistoryDuplicates;
this.crlfDelay = crlfDelay ?
Math.max(kMincrlfDelay, crlfDelay) : kMincrlfDelay;
// Check arity, 2 - for async, 1 for sync
if (typeof completer === 'function') {
this.completer = completer.length === 2 ?
completer :
function completerWrapper(v, cb) {
cb(null, completer(v));
};
}
this.setPrompt(prompt);
this.terminal = !!terminal;
function ondata(data) {
self._normalWrite(data);
}
function onend() {
if (typeof self._line_buffer === 'string' &&
self._line_buffer.length > 0) {
self.emit('line', self._line_buffer);
}
self.close();
}
function ontermend() {
if (typeof self.line === 'string' && self.line.length > 0) {
self.emit('line', self.line);
}
self.close();
}
function onkeypress(s, key) {
self._ttyWrite(s, key);
if (key && key.sequence) {
// if the key.sequence is half of a surrogate pair
// (>= 0xd800 and <= 0xdfff), refresh the line so
// the character is displayed appropriately.
const ch = key.sequence.codePointAt(0);
if (ch >= 0xd800 && ch <= 0xdfff)
self._refreshLine();
}
}
function onresize() {
self._refreshLine();
}
if (!this.terminal) {
function onSelfCloseWithoutTerminal() {
input.removeListener('data', ondata);
input.removeListener('end', onend);
}
input.on('data', ondata);
input.on('end', onend);
self.once('close', onSelfCloseWithoutTerminal);
this._decoder = new StringDecoder('utf8');
} else {
function onSelfCloseWithTerminal() {
input.removeListener('keypress', onkeypress);
input.removeListener('end', ontermend);
if (output !== null && output !== undefined) {
output.removeListener('resize', onresize);
}
}
emitKeypressEvents(input, this);
// input usually refers to stdin
input.on('keypress', onkeypress);
input.on('end', ontermend);
// Current line
this.line = '';
this._setRawMode(true);
this.terminal = true;
// Cursor position on the line.
this.cursor = 0;
this.history = [];
this.historyIndex = -1;
if (output !== null && output !== undefined)
output.on('resize', onresize);
self.once('close', onSelfCloseWithTerminal);
}
input.resume();
}
inherits(Interface, EventEmitter);
Object.defineProperty(Interface.prototype, 'columns', {
configurable: true,
enumerable: true,
get: function() {
var columns = Infinity;
if (this.output && this.output.columns)
columns = this.output.columns;
return columns;
}
});
Interface.prototype.setPrompt = function(prompt) {
this._prompt = prompt;
};
Interface.prototype._setRawMode = function(mode) {
const wasInRawMode = this.input.isRaw;
if (typeof this.input.setRawMode === 'function') {
this.input.setRawMode(mode);
}
return wasInRawMode;
};
Interface.prototype.prompt = function(preserveCursor) {
if (this.paused) this.resume();
if (this.terminal) {
if (!preserveCursor) this.cursor = 0;
this._refreshLine();
} else {
this._writeToOutput(this._prompt);
}
};
Interface.prototype.question = function(query, cb) {
if (typeof cb === 'function') {
if (this._questionCallback) {
this.prompt();
} else {
this._oldPrompt = this._prompt;
this.setPrompt(query);
this._questionCallback = cb;
this.prompt();
}
}
};
Interface.prototype._onLine = function(line) {
if (this._questionCallback) {
var cb = this._questionCallback;
this._questionCallback = null;
this.setPrompt(this._oldPrompt);
cb(line);
} else {
this.emit('line', line);
}
};
Interface.prototype._writeToOutput = function _writeToOutput(stringToWrite) {
if (typeof stringToWrite !== 'string') {
throw new errors.TypeError(
'ERR_INVALID_ARG_TYPE',
'stringToWrite',
'string',
stringToWrite
);
}
if (this.output !== null && this.output !== undefined) {
this.output.write(stringToWrite);
}
};
Interface.prototype._addHistory = function() {
if (this.line.length === 0) return '';
// if the history is disabled then return the line
if (this.historySize === 0) return this.line;
// if the trimmed line is empty then return the line
if (this.line.trim().length === 0) return this.line;
if (this.history.length === 0 || this.history[0] !== this.line) {
if (this.removeHistoryDuplicates) {
// Remove older history line if identical to new one
const dupIndex = this.history.indexOf(this.line);
if (dupIndex !== -1) this.history.splice(dupIndex, 1);
}
this.history.unshift(this.line);
// Only store so many
if (this.history.length > this.historySize) this.history.pop();
}
this.historyIndex = -1;
return this.history[0];
};
Interface.prototype._refreshLine = function() {
// line length
var line = this._prompt + this.line;
var dispPos = this._getDisplayPos(line);
var lineCols = dispPos.cols;
var lineRows = dispPos.rows;
// cursor position
var cursorPos = this._getCursorPos();
// first move to the bottom of the current line, based on cursor pos
var prevRows = this.prevRows || 0;
if (prevRows > 0) {
moveCursor(this.output, 0, -prevRows);
}
// Cursor to left edge.
cursorTo(this.output, 0);
// erase data
clearScreenDown(this.output);
// Write the prompt and the current buffer content.
this._writeToOutput(line);
// Force terminal to allocate a new line
if (lineCols === 0) {
this._writeToOutput(' ');
}
// Move cursor to original position.
cursorTo(this.output, cursorPos.cols);
var diff = lineRows - cursorPos.rows;
if (diff > 0) {
moveCursor(this.output, 0, -diff);
}
this.prevRows = cursorPos.rows;
};
Interface.prototype.close = function() {
if (this.closed) return;
this.pause();
if (this.terminal) {
this._setRawMode(false);
}
this.closed = true;
this.emit('close');
};
Interface.prototype.pause = function() {
if (this.paused) return;
this.input.pause();
this.paused = true;
this.emit('pause');
return this;
};
Interface.prototype.resume = function() {
if (!this.paused) return;
this.input.resume();
this.paused = false;
this.emit('resume');
return this;
};
Interface.prototype.write = function(d, key) {
if (this.paused) this.resume();
this.terminal ? this._ttyWrite(d, key) : this._normalWrite(d);
};
Interface.prototype._normalWrite = function(b) {
if (b === undefined) {
return;
}
var string = this._decoder.write(b);
if (this._sawReturnAt &&
now() - this._sawReturnAt <= this.crlfDelay) {
string = string.replace(/^\n/, '');
this._sawReturnAt = 0;
}
// Run test() on the new string chunk, not on the entire line buffer.
var newPartContainsEnding = lineEnding.test(string);
if (this._line_buffer) {
string = this._line_buffer + string;
this._line_buffer = null;
}
if (newPartContainsEnding) {
this._sawReturnAt = string.endsWith('\r') ? now() : 0;
// got one or more newlines; process into "line" events
var lines = string.split(lineEnding);
// either '' or (conceivably) the unfinished portion of the next line
string = lines.pop();
this._line_buffer = string;
for (var n = 0; n < lines.length; n++)
this._onLine(lines[n]);
} else if (string) {
// no newlines this time, save what we have for next time
this._line_buffer = string;
}
};
Interface.prototype._insertString = function(c) {
if (this.cursor < this.line.length) {
var beg = this.line.slice(0, this.cursor);
var end = this.line.slice(this.cursor, this.line.length);
this.line = beg + c + end;
this.cursor += c.length;
this._refreshLine();
} else {
this.line += c;
this.cursor += c.length;
if (this._getCursorPos().cols === 0) {
this._refreshLine();
} else {
this._writeToOutput(c);
}
// a hack to get the line refreshed if it's needed
this._moveCursor(0);
}
};
Interface.prototype._tabComplete = function(lastKeypressWasTab) {
var self = this;
self.pause();
self.completer(self.line.slice(0, self.cursor), function onComplete(err, rv) {
self.resume();
if (err) {
debug('tab completion error %j', err);
return;
}
const completions = rv[0];
const completeOn = rv[1]; // the text that was completed
if (completions && completions.length) {
// Apply/show completions.
if (lastKeypressWasTab) {
self._writeToOutput('\r\n');
var width = completions.reduce(function completionReducer(a, b) {
return a.length > b.length ? a : b;
}).length + 2; // 2 space padding
var maxColumns = Math.floor(self.columns / width);
if (!maxColumns || maxColumns === Infinity) {
maxColumns = 1;
}
var group = [];
for (var i = 0; i < completions.length; i++) {
var c = completions[i];
if (c === '') {
handleGroup(self, group, width, maxColumns);
group = [];
} else {
group.push(c);
}
}
handleGroup(self, group, width, maxColumns);
}
// If there is a common prefix to all matches, then apply that portion.
var f = completions.filter(function completionFilter(e) {
if (e) return e;
});
var prefix = commonPrefix(f);
if (prefix.length > completeOn.length) {
self._insertString(prefix.slice(completeOn.length));
}
self._refreshLine();
}
});
};
// this = Interface instance
function handleGroup(self, group, width, maxColumns) {
if (group.length === 0) {
return;
}
var minRows = Math.ceil(group.length / maxColumns);
for (var row = 0; row < minRows; row++) {
for (var col = 0; col < maxColumns; col++) {
var idx = row * maxColumns + col;
if (idx >= group.length) {
break;
}
var item = group[idx];
self._writeToOutput(item);
if (col < maxColumns - 1) {
for (var s = 0; s < width - item.length; s++) {
self._writeToOutput(' ');
}
}
}
self._writeToOutput('\r\n');
}
self._writeToOutput('\r\n');
}
function commonPrefix(strings) {
if (!strings || strings.length === 0) {
return '';
}
if (strings.length === 1) return strings[0];
var sorted = strings.slice().sort();
var min = sorted[0];
var max = sorted[sorted.length - 1];
for (var i = 0, len = min.length; i < len; i++) {
if (min[i] !== max[i]) {
return min.slice(0, i);
}
}
return min;
}
Interface.prototype._wordLeft = function() {
if (this.cursor > 0) {
var leading = this.line.slice(0, this.cursor);
var match = leading.match(/(?:[^\w\s]+|\w+|)\s*$/);
this._moveCursor(-match[0].length);
}
};
Interface.prototype._wordRight = function() {
if (this.cursor < this.line.length) {
var trailing = this.line.slice(this.cursor);
var match = trailing.match(/^(?:\s+|\W+|\w+)\s*/);
this._moveCursor(match[0].length);
}
};
Interface.prototype._deleteLeft = function() {
if (this.cursor > 0 && this.line.length > 0) {
this.line = this.line.slice(0, this.cursor - 1) +
this.line.slice(this.cursor, this.line.length);
this.cursor--;
this._refreshLine();
}
};
Interface.prototype._deleteRight = function() {
this.line = this.line.slice(0, this.cursor) +
this.line.slice(this.cursor + 1, this.line.length);
this._refreshLine();
};
Interface.prototype._deleteWordLeft = function() {
if (this.cursor > 0) {
var leading = this.line.slice(0, this.cursor);
var match = leading.match(/(?:[^\w\s]+|\w+|)\s*$/);
leading = leading.slice(0, leading.length - match[0].length);
this.line = leading + this.line.slice(this.cursor, this.line.length);
this.cursor = leading.length;
this._refreshLine();
}
};
Interface.prototype._deleteWordRight = function() {
if (this.cursor < this.line.length) {
var trailing = this.line.slice(this.cursor);
var match = trailing.match(/^(?:\s+|\W+|\w+)\s*/);
this.line = this.line.slice(0, this.cursor) +
trailing.slice(match[0].length);
this._refreshLine();
}
};
Interface.prototype._deleteLineLeft = function() {
this.line = this.line.slice(this.cursor);
this.cursor = 0;
this._refreshLine();
};
Interface.prototype._deleteLineRight = function() {
this.line = this.line.slice(0, this.cursor);
this._refreshLine();
};
Interface.prototype.clearLine = function() {
this._moveCursor(+Infinity);
this._writeToOutput('\r\n');
this.line = '';
this.cursor = 0;
this.prevRows = 0;
};
Interface.prototype._line = function() {
var line = this._addHistory();
this.clearLine();
this._onLine(line);
};
Interface.prototype._historyNext = function() {
if (this.historyIndex > 0) {
this.historyIndex--;
this.line = this.history[this.historyIndex];
this.cursor = this.line.length; // set cursor to end of line.
this._refreshLine();
} else if (this.historyIndex === 0) {
this.historyIndex = -1;
this.cursor = 0;
this.line = '';
this._refreshLine();
}
};
Interface.prototype._historyPrev = function() {
if (this.historyIndex + 1 < this.history.length) {
this.historyIndex++;
this.line = this.history[this.historyIndex];
this.cursor = this.line.length; // set cursor to end of line.
this._refreshLine();
}
};
// Returns the last character's display position of the given string
Interface.prototype._getDisplayPos = function(str) {
var offset = 0;
var col = this.columns;
var row = 0;
var code;
str = stripVTControlCharacters(str);
for (var i = 0, len = str.length; i < len; i++) {
code = str.codePointAt(i);
if (code >= 0x10000) { // surrogates
i++;
}
if (code === 0x0a) { // new line \n
offset = 0;
row += 1;
continue;
}
const width = getStringWidth(code);
if (width === 0 || width === 1) {
offset += width;
} else { // width === 2
if ((offset + 1) % col === 0) {
offset++;
}
offset += 2;
}
}
var cols = offset % col;
var rows = row + (offset - cols) / col;
return { cols: cols, rows: rows };
};
// Returns current cursor's position and line
Interface.prototype._getCursorPos = function() {
var columns = this.columns;
var strBeforeCursor = this._prompt + this.line.substring(0, this.cursor);
var dispPos = this._getDisplayPos(stripVTControlCharacters(strBeforeCursor));
var cols = dispPos.cols;
var rows = dispPos.rows;
// If the cursor is on a full-width character which steps over the line,
// move the cursor to the beginning of the next line.
if (cols + 1 === columns &&
this.cursor < this.line.length &&
isFullWidthCodePoint(this.line.codePointAt(this.cursor))) {
rows++;
cols = 0;
}
return { cols: cols, rows: rows };
};
// This function moves cursor dx places to the right
// (-dx for left) and refreshes the line if it is needed
Interface.prototype._moveCursor = function(dx) {
var oldcursor = this.cursor;
var oldPos = this._getCursorPos();
this.cursor += dx;
// bounds check
if (this.cursor < 0) this.cursor = 0;
else if (this.cursor > this.line.length) this.cursor = this.line.length;
var newPos = this._getCursorPos();
// check if cursors are in the same line
if (oldPos.rows === newPos.rows) {
var diffCursor = this.cursor - oldcursor;
var diffWidth;
if (diffCursor < 0) {
diffWidth = -getStringWidth(
this.line.substring(this.cursor, oldcursor)
);
} else if (diffCursor > 0) {
diffWidth = getStringWidth(
this.line.substring(this.cursor, oldcursor)
);
}
moveCursor(this.output, diffWidth, 0);
this.prevRows = newPos.rows;
} else {
this._refreshLine();
}
};
// handle a write from the tty
Interface.prototype._ttyWrite = function(s, key) {
const previousKey = this._previousKey;
key = key || {};
this._previousKey = key;
// Ignore escape key - Fixes #2876
if (key.name === 'escape') return;
if (key.ctrl && key.shift) {
/* Control and shift pressed */
switch (key.name) {
case 'backspace':
this._deleteLineLeft();
break;
case 'delete':
this._deleteLineRight();
break;
}
} else if (key.ctrl) {
/* Control key pressed */
switch (key.name) {
case 'c':
if (this.listenerCount('SIGINT') > 0) {
this.emit('SIGINT');
} else {
// This readline instance is finished
this.close();
}
break;
case 'h': // delete left
this._deleteLeft();
break;
case 'd': // delete right or EOF
if (this.cursor === 0 && this.line.length === 0) {
// This readline instance is finished
this.close();
} else if (this.cursor < this.line.length) {
this._deleteRight();
}
break;
case 'u': // delete the whole line
this.cursor = 0;
this.line = '';
this._refreshLine();
break;
case 'k': // delete from current to end of line
this._deleteLineRight();
break;
case 'a': // go to the start of the line
this._moveCursor(-Infinity);
break;
case 'e': // go to the end of the line
this._moveCursor(+Infinity);
break;
case 'b': // back one character
this._moveCursor(-1);
break;
case 'f': // forward one character
this._moveCursor(+1);
break;
case 'l': // clear the whole screen
cursorTo(this.output, 0, 0);
clearScreenDown(this.output);
this._refreshLine();
break;
case 'n': // next history item
this._historyNext();
break;
case 'p': // previous history item
this._historyPrev();
break;
case 'z':
if (process.platform === 'win32') break;
if (this.listenerCount('SIGTSTP') > 0) {
this.emit('SIGTSTP');
} else {
process.once('SIGCONT', (function(self) {
return function() {
// Don't raise events if stream has already been abandoned.
if (!self.paused) {
// Stream must be paused and resumed after SIGCONT to catch
// SIGINT, SIGTSTP, and EOF.
self.pause();
self.emit('SIGCONT');
}
// explicitly re-enable "raw mode" and move the cursor to
// the correct position.
// See https://github.com/joyent/node/issues/3295.
self._setRawMode(true);
self._refreshLine();
};
})(this));
this._setRawMode(false);
process.kill(process.pid, 'SIGTSTP');
}
break;
case 'w': // delete backwards to a word boundary
case 'backspace':
this._deleteWordLeft();
break;
case 'delete': // delete forward to a word boundary
this._deleteWordRight();
break;
case 'left':
this._wordLeft();
break;
case 'right':
this._wordRight();
break;
}
} else if (key.meta) {
/* Meta key pressed */
switch (key.name) {
case 'b': // backward word
this._wordLeft();
break;
case 'f': // forward word
this._wordRight();
break;
case 'd': // delete forward word
case 'delete':
this._deleteWordRight();
break;
case 'backspace': // delete backwards to a word boundary
this._deleteWordLeft();
break;
}
} else {
/* No modifier keys used */
// \r bookkeeping is only relevant if a \n comes right after.
if (this._sawReturnAt && key.name !== 'enter')
this._sawReturnAt = 0;
switch (key.name) {
case 'return': // carriage return, i.e. \r
this._sawReturnAt = now();
this._line();
break;
case 'enter':
// When key interval > crlfDelay
if (this._sawReturnAt === 0 ||
now() - this._sawReturnAt > this.crlfDelay) {
this._line();
}
this._sawReturnAt = 0;
break;
case 'backspace':
this._deleteLeft();
break;
case 'delete':
this._deleteRight();
break;
case 'left':
this._moveCursor(-1);
break;
case 'right':
this._moveCursor(+1);
break;
case 'home':
this._moveCursor(-Infinity);
break;
case 'end':
this._moveCursor(+Infinity);
break;
case 'up':
this._historyPrev();
break;
case 'down':
this._historyNext();
break;
case 'tab':
// If tab completion enabled, do that...
if (typeof this.completer === 'function' && this.isCompletionEnabled) {
const lastKeypressWasTab = previousKey && previousKey.name === 'tab';
this._tabComplete(lastKeypressWasTab);
break;
}
// falls through
default:
if (s instanceof Buffer)
s = s.toString('utf-8');
if (s) {
var lines = s.split(/\r\n|\n|\r/);
for (var i = 0, len = lines.length; i < len; i++) {
if (i > 0) {
this._line();
}
this._insertString(lines[i]);
}
}
}
}
};
/**
* accepts a readable Stream instance and makes it emit "keypress" events
*/
function emitKeypressEvents(stream, iface) {
if (stream[KEYPRESS_DECODER]) return;
stream[KEYPRESS_DECODER] = new StringDecoder('utf8');
stream[ESCAPE_DECODER] = emitKeys(stream);
stream[ESCAPE_DECODER].next();
const escapeCodeTimeout = () => stream[ESCAPE_DECODER].next('');
let timeoutId;
function onData(b) {
if (stream.listenerCount('keypress') > 0) {
var r = stream[KEYPRESS_DECODER].write(b);
if (r) {
clearTimeout(timeoutId);
if (iface) {
iface._sawKeyPress = r.length === 1;
}
for (var i = 0; i < r.length; i++) {
if (r[i] === '\t' && typeof r[i + 1] === 'string' && iface) {
iface.isCompletionEnabled = false;
}
try {
stream[ESCAPE_DECODER].next(r[i]);
// Escape letter at the tail position
if (r[i] === kEscape && i + 1 === r.length) {
timeoutId = setTimeout(escapeCodeTimeout, ESCAPE_CODE_TIMEOUT);
}
} catch (err) {
// if the generator throws (it could happen in the `keypress`
// event), we need to restart it.
stream[ESCAPE_DECODER] = emitKeys(stream);
stream[ESCAPE_DECODER].next();
throw err;
} finally {
if (iface) {
iface.isCompletionEnabled = true;
}
}
}
}
} else {
// Nobody's watching anyway
stream.removeListener('data', onData);
stream.on('newListener', onNewListener);
}
}
function onNewListener(event) {
if (event === 'keypress') {
stream.on('data', onData);
stream.removeListener('newListener', onNewListener);
}
}
if (stream.listenerCount('keypress') > 0) {
stream.on('data', onData);
} else {
stream.on('newListener', onNewListener);
}
}
/**
* moves the cursor to the x and y coordinate on the given stream
*/
function cursorTo(stream, x, y) {
if (stream === null || stream === undefined)
return;
if (typeof x !== 'number' && typeof y !== 'number')
return;
if (typeof x !== 'number')
throw new errors.Error('ERR_INVALID_CURSOR_POS');
if (typeof y !== 'number') {
stream.write(CSI`${x + 1}G`);
} else {
stream.write(CSI`${y + 1};${x + 1}H`);
}
}
/**
* moves the cursor relative to its current location
*/
function moveCursor(stream, dx, dy) {
if (stream === null || stream === undefined)
return;
if (dx < 0) {
stream.write(CSI`${-dx}D`);
} else if (dx > 0) {
stream.write(CSI`${dx}C`);
}
if (dy < 0) {
stream.write(CSI`${-dy}A`);
} else if (dy > 0) {
stream.write(CSI`${dy}B`);
}
}
/**
* 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) {
if (stream === null || stream === undefined)
return;
if (dir < 0) {
// to the beginning
stream.write(kClearToBeginning);
} else if (dir > 0) {
// to the end
stream.write(kClearToEnd);
} else {
// entire line
stream.write(kClearLine);
}
}
/**
* clears the screen from the current position of the cursor down
*/
function clearScreenDown(stream) {
if (stream === null || stream === undefined)
return;
stream.write(kClearScreenDown);
}
module.exports = {
Interface,
clearLine,
clearScreenDown,
createInterface,
cursorTo,
emitKeypressEvents,
moveCursor
};