node-scanf

Do you want simplely shell script input which have formats and sync return?

Do you want a sscanf like function to parse format strings?

scanf is a C like scanf/sscanf module for node.js which can help you with that.

Documentation

• Example
• Quickly start
• C like format
• Return
• Directly return
• Array return
• Json return
• Detect end of input
• sscanf

Installation

npm install scanf

CI

The project is tested on GitHub Actions across the following platforms:

OS	Node.js versions
Ubuntu	4.x ~ 22.x
Windows	4.x ~ 22.x
macOS	16.x ~ 22.x (arm64)

macOS CI only covers Node.js 16+ because the latest macOS runner (macos-latest) runs on Apple Silicon (arm64), which does not provide prebuilt binaries for older Node.js versions. The Intel-based macos-13 runner is no longer available.

Format support now

• %d - integer
• %f - float
• %s - string
• %S - string of line
• %x - hex
• %a - hex float
• %o - octal

Example

Quickly start

var scanf = require('scanf');

console.log('Pleas input your name');
var name = scanf('%s');

console.log('Pleas input your age');
var age = scanf('%d');

console.log('your name [%s] type: [%s]', name, typeof name);
console.log('your age [%s] type: [%s]', age, typeof age);

REPL

Pleas input your name
> Barack\ Obama
Pleas input your age
> 24
your name [Barack Obama] type: [string]
your age [24] type: [number]

C like format

var scanf = require('scanf');

console.log('when are you born? \(Year-month-day\)');
var date = scanf('%d-%d-%d');

console.log('your birthday [%s]', date);

REPL

when are you born? (Year-month-day)
> 1990-01-01
your birthday [1990,1,1]

Return

Directly return

var scanf = require('scanf');

var number = scanf('%d');

console.log('number', number);

REPL

>> 2015    
number 2015

Array return

var scanf = require('scanf');

var result = scanf('%s%d%d');

console.log('result', result);

REPL

>> Alan 24 180        
result [ 'Alan', 24, 180 ]

Json return

var scanf = require('scanf');

var result = scanf('%d %f %s %x %o', 'integer', 'float', 'string', 'hex', 'octal');

console.log('result', result);

REPL

>> 12 3.1415926 hello 1F 10    
result { 
  integer: 12,
  float: 3.1415926,
  string: 'hello',
  hex: 31,
  octal: 8 
}

Detect end of input

After calling scanf(), use scanf.isEOF() to check whether the read reached the end of standard input. This is different from an empty line or input that does not match the requested format.

var scanf = require('scanf');

while (true) {
  var values = scanf('%d %d %d');

  if (scanf.isEOF()) {
    break;
  }

  console.log(values[0], values[1], values[2]);
}

EOF is reported only after a read attempts to go past the available input. In a terminal, send EOF with Ctrl+D on macOS/Linux, or Ctrl+Z followed by Enter on Windows.

sscanf

REPL

>> var sscanf = require('scanf').sscanf;
undefined
>> sscanf('12 34', '%d');
12
>> sscanf('Alan 20 180', '%s%d%d')
[ 'Alan', 20, 180 ]
>> sscanf('12 3.1415926 hello', '%d %f %s', 'month', 'pi', 'world');
{ month: 12, pi: 3.1415926, world: 'hello' }
>> sscanf('   14   ??  Ss     0:07.59 /usr/sbin/securityd -i', '%d %s %s %s %s %s', 'pid', 'tty', 'stat', 'time', 'exec', 'param');
{ pid: 14,
  tty: '??',
  stat: 'Ss',
  time: '0:07.59',
  exec: '/usr/sbin/securityd',
  param: '-i' }

you can see the ./tests files for more detail.

If there are some formats not support or go broken, you can contact author with email lellansin@gmail.com.

Contributors

• lellansin
• piranna
• samchon

License

MIT