format

What is format?

The 'format' npm package is designed to provide string formatting capabilities similar to the sprintf function in C or Python's str.format(). It allows users to embed variables inside a string template with a specific format, making it easier to generate formatted messages or strings dynamically.

What are format's main functionalities?

String substitution

This feature allows for simple substitution of strings into a template. The '%s' specifier is replaced by the 'World' string, resulting in 'Hello, World'.

"Hello, %s".format('World')

Number formatting

Enables formatting of numbers with fixed decimal places. Here, '%.2f' formats the number to two decimal places, resulting in 'Your balance is $123.46'.

"Your balance is $%.2f".format(123.456)

JSON object substitution

Allows embedding JSON objects directly into the string. '%j' is replaced with the JSON string representation of the object, producing a string like '{"name":"John","age":30}'.

"%j".format({name: 'John', age: 30})

Other packages similar to format

sprintf-js

Provides similar functionality to 'format' with additional support for positional arguments and a wider range of format specifiers. It's more closely aligned with the sprintf function in C.

string-template

Offers a simpler approach to string formatting, using named placeholders instead of format specifiers. It's more intuitive for basic use cases but lacks the advanced formatting options available in 'format'.

README

format

printf, sprintf, and vsprintf for JavaScript

Installation

npm install format

The code works in browsers as well, you can copy these functions into your project or otherwise include them with your other JavaScript.

Usage

var format = require('format')
  , printf = format.printf
  , vsprintf = format.vsprintf
  // or if you want to keep it old school
  , sprintf = format

// Print 'hello world'
printf('%s world', 'hello')

var what = 'life, the universe, and everything'
format('%d is the answer to %s', 42, what)
// => '42 is the answer to life, the universe, and everything'

vsprintf('%d is the answer to %s', [42, what])
// => '42 is the answer to life, the universe, and everything'

Supported format specifiers: b, c, d, f, o, s, x, and X.

See man 3 printf or man 1 printf for details.

Precision is supported for floating point numbers.

License

Copyright 2010 - 2014 Sami Samhuri [e-mail]

MIT license