String.format for JavaScript

This is a JavaScript library for string, date and number formatting. Formatting is done using format strings almost completely compatible with the String.Format method in Microsoft .NET Framework.

How to use

To use the library, include the library itself and optionally the cultures you are targetting. Note that if no culture files are included, the invariant culture will be used.

<script type="text/javascript" src="stringformat-X.XX.min.js"></script>
<script type="text/javascript" src="cultures/stringformat.en.js"></script>
<script type="text/javascript" src="cultures/stringformat.sv.js"></script>

Then you're ready to go. Here are two simple examples using indexes and object paths/named parameters.

// Index
String.format(
    "Welcome back, {0}! Last seen {1:M}", 
    "John Doe", new Date(1985, 3, 7, 12, 33)
    );
    
// Outputs: 
// Welcome back, John Doe! Last seen April 07

// Named parameters
String.format(
    "Welcome back, {user.name}! Last seen {lastseen:M}", 
    { 
        user: {
            name : "John Doe", 
            age : 42
        },
        lastseen: new Date(2009, 3, 7, 12, 33) 
    });
    
// Outputs: 
// Welcome back, John Doe! Last seen April 07

By default the browser culture will be used, given that the appropriate culture file has been referenced from the page. To set culture explicitly, use the sffjs.setCulture method, which accepts a IETF language code.

sffjs.setCulture("sv");

See more

• Usage examples
• Reference information regarding .NET format strings

Compatibility with .NET implementation

The output of this library is highly compatible with the output from the .NET implementation. In this section differences will be listed

• Date format
  • Date format specifier O is not supported
  • Date format specifier R is not supported
• Number format
  • Number format specifier c ignores specified precision

Other types does not have a format implementation, and is thus serialized to a string by the __Format function or the Javascript runtime using the toString function.

These are additions in this implementation, and thus not supported by the .NET implementation:

• Object paths/named parameters