To use this module, do require('readline'). Readline allows reading of a\nstream (such as process.stdin) on a line-by-line basis.
Note that once you've invoked this module, your Node.js program will not\nterminate until you've closed the interface. Here's how to allow your\nprogram to gracefully exit:
\nconst readline = require('readline');\n\nconst rl = readline.createInterface({\n input: process.stdin,\n output: process.stdout\n});\n\nrl.question('What do you think of Node.js? ', (answer) => {\n // TODO: Log the answer in a database\n console.log('Thank you for your valuable feedback:', answer);\n\n rl.close();\n});\nThe class that represents a readline interface with an input and output\nstream.
\n", "methods": [ { "textRaw": "rl.close()", "type": "method", "name": "close", "meta": { "added": [ "v0.1.98" ] }, "desc": "Closes the Interface instance, relinquishing control on the input and\noutput streams. The 'close' event will also be emitted.
Pauses the readline input stream, allowing it to be resumed later if needed.
Note that this doesn't immediately pause the stream of events. Several events may\nbe emitted after calling pause, including line.
Readies readline for input from the user, putting the current setPrompt\noptions on a new line, giving the user a new spot to write. Set preserveCursor\nto true to prevent the cursor placement being reset to 0.
This will also resume the input stream used with createInterface if it has\nbeen paused.
If output is set to null or undefined when calling createInterface, the\nprompt is not written.
Prepends the prompt with query and invokes callback with the user's\nresponse. Displays the query to the user, and then invokes callback\nwith the user's response after it has been typed.
This will also resume the input stream used with createInterface if\nit has been paused.
If output is set to null or undefined when calling createInterface,\nnothing is displayed.
Example usage:
\nrl.question('What is your favorite food?', (answer) => {\n console.log(`Oh, so your favorite food is ${answer}`);\n});\nResumes the readline input stream.
Sets the prompt, for example when you run node on the command line, you see\n>, which is Node.js's prompt.
Writes data to output stream, unless output is set to null or\nundefined when calling createInterface. key is an object literal to\nrepresent a key sequence; available if the terminal is a TTY.
This will also resume the input stream if it has been paused.
Example:
\nrl.write('Delete me!');\n// Simulate ctrl+u to delete the line written previously\nrl.write(null, {ctrl: true, name: 'u'});\nfunction () {}
Emitted when close() is called.
Also emitted when the input stream receives its 'end' event. The Interface\ninstance should be considered "finished" once this is emitted. For example, when\nthe input stream receives ^D, respectively known as EOT.
This event is also called if there is no SIGINT event listener present when\nthe input stream receives a ^C, respectively known as SIGINT.
function (line) {}
Emitted whenever the input stream receives an end of line (\\n, \\r, or\n\\r\\n), usually received when the user hits enter, or return. This is a good\nhook to listen for user input.
Example of listening for 'line':
rl.on('line', (cmd) => {\n console.log(`You just typed: ${cmd}`);\n});\nfunction () {}
Emitted whenever the input stream is paused.
Also emitted whenever the input stream is not paused and receives the\nSIGCONT event. (See events SIGTSTP and SIGCONT)
Example of listening for 'pause':
rl.on('pause', () => {\n console.log('Readline paused.');\n});\nfunction () {}
Emitted whenever the input stream is resumed.
Example of listening for 'resume':
rl.on('resume', () => {\n console.log('Readline resumed.');\n});\nfunction () {}
This does not work on Windows.
\nEmitted whenever the input stream is sent to the background with ^Z,\nrespectively known as SIGTSTP, and then continued with fg(1). This event\nonly emits if the stream was not paused before sending the program to the\nbackground.
Example of listening for SIGCONT:
rl.on('SIGCONT', () => {\n // `prompt` will automatically resume the stream\n rl.prompt();\n});\nfunction () {}
Emitted whenever the input stream receives a ^C, respectively known as\nSIGINT. If there is no SIGINT event listener present when the input\nstream receives a SIGINT, pause will be triggered.
Example of listening for SIGINT:
rl.on('SIGINT', () => {\n rl.question('Are you sure you want to exit?', (answer) => {\n if (answer.match(/^y(es)?$/i)) rl.pause();\n });\n});\nfunction () {}
This does not work on Windows.
\nEmitted whenever the input stream receives a ^Z, respectively known as\nSIGTSTP. If there is no SIGTSTP event listener present when the input\nstream receives a SIGTSTP, the program will be sent to the background.
When the program is resumed with fg, the 'pause' and SIGCONT events will be\nemitted. You can use either to resume the stream.
The 'pause' and SIGCONT events will not be triggered if the stream was paused\nbefore the program was sent to the background.
Example of listening for SIGTSTP:
rl.on('SIGTSTP', () => {\n // This will override SIGTSTP and prevent the program from going to the\n // background.\n console.log('Caught SIGTSTP.');\n});\nHere's an example of how to use all these together to craft a tiny command\nline interface:
\nconst readline = require('readline');\nconst rl = readline.createInterface(process.stdin, process.stdout);\n\nrl.setPrompt('OHAI> ');\nrl.prompt();\n\nrl.on('line', (line) => {\n switch(line.trim()) {\n case 'hello':\n console.log('world!');\n break;\n default:\n console.log('Say what? I might have heard `' + line.trim() + '`');\n break;\n }\n rl.prompt();\n}).on('close', () => {\n console.log('Have a great day!');\n process.exit(0);\n});\nA common case for readline's input option is to pass a filesystem readable\nstream to it. This is how one could craft line-by-line parsing of a file:
const readline = require('readline');\nconst fs = require('fs');\n\nconst rl = readline.createInterface({\n input: fs.createReadStream('sample.txt')\n});\n\nrl.on('line', (line) => {\n console.log('Line from file:', line);\n});\nNote: The rl.write() method will write the data to the readline\nInterface's input as if it were provided by the user.
Clears current line of given TTY stream in a specified direction.\ndir should have one of following values:
-1 - to the left from cursor1 - to the right from cursor0 - the entire lineClears the screen from the current position of the cursor down.
\n", "signatures": [ { "params": [ { "name": "stream" } ] } ] }, { "textRaw": "readline.createInterface(options)", "type": "method", "name": "createInterface", "meta": { "added": [ "v0.1.98" ] }, "desc": "Creates a readline Interface instance. Accepts an options Object that takes\nthe following values:
input - the readable stream to listen to (Required).
output - the writable stream to write readline data to (Optional).
completer - an optional function that is used for Tab autocompletion. See\nbelow for an example of using this.
terminal - pass true if the input and output streams should be\ntreated like a TTY, and have ANSI/VT100 escape codes written to it.\nDefaults to checking isTTY on the output stream upon instantiation.
historySize - maximum number of history lines retained. Defaults to 30.
The completer function is given the current line entered by the user, and\nis supposed to return an Array with 2 entries:
An Array with matching entries for the completion.
\nThe substring that was used for the matching.
\nWhich ends up looking something like:\n[[substr1, substr2, ...], originalsubstring].
Example:
\nfunction completer(line) {\n var completions = '.help .error .exit .quit .q'.split(' ')\n var hits = completions.filter((c) => { return c.indexOf(line) == 0 })\n // show all completions if none found\n return [hits.length ? hits : completions, line]\n}\nAlso completer can be run in async mode if it accepts two arguments:
function completer(linePartial, callback) {\n callback(null, [['123'], linePartial]);\n}\ncreateInterface is commonly used with process.stdin and\nprocess.stdout in order to accept user input:
const readline = require('readline');\nconst rl = readline.createInterface({\n input: process.stdin,\n output: process.stdout\n});\nOnce you have a readline instance, you most commonly listen for the\n'line' event.
If terminal is true for this instance then the output stream will get\nthe best compatibility if it defines an output.columns property, and fires\na 'resize' event on the output if/when the columns ever change\n(process.stdout does this automatically when it is a TTY).
Move cursor to the specified position in a given TTY stream.
\n", "signatures": [ { "params": [ { "name": "stream" }, { "name": "x" }, { "name": "y" } ] } ] }, { "textRaw": "readline.emitKeypressEvents(stream[, interface])", "type": "method", "name": "emitKeypressEvents", "meta": { "added": [ "v0.7.7" ] }, "desc": "Causes stream to begin emitting 'keypress' events corresponding to its\ninput.\nOptionally, interface specifies a readline.Interface instance for which\nautocompletion is disabled when copy-pasted input is detected.
Move cursor relative to it's current position in a given TTY stream.
\n", "signatures": [ { "params": [ { "name": "stream" }, { "name": "dx" }, { "name": "dy" } ] } ] } ], "type": "module", "displayName": "Readline" } ] }