qb-format-s

A tiny implementation of printf's spacing logic for strings (~500 added bytes to minified codebase). Only supports %s, not numbers, floats, etc.

Complies with the 100% test coverage and minimum dependency requirements of qb-standard .

Install

npm install qb-format-s

Examples

qb-format-s has very similar behavior to the standard printf library function for string formatting *.

var format = require('qb-format-s')

format( 'a%sz}',    '12345678' )    // returns 'a12345678z'
format( 'a%s9z',    '12345678' )    // returns 'a 12345678z'  (field-width 9)
format( 'a%s9.4z',  '12345678' )    // returns 'a     1234z'  (field-width 9, truncate 4)
format( 'a%-s9.4z', '12345678' )    // returns 'a1234     z'  (truncate 4, left-justified) 

To log formatted output, you might try wrapping qb-format-s in a small function:

function logf() {
    console.log( 
        format.apply( 
            null, 
            Array.prototype.slice.call(arguments).map(function(v) { return v + '' } ) 
        ) 
    )
}

logf( 'a%-s9.4z', '12345678' )
> a1234     z

mismatched input

* qb-format-s is more forgiving than printf in that it applies arguments to the expression until it has no more arguments to apply. Leftover '%s' expressions are returned without change. Passing no arguments to qb-format-s will return empty string.

format()
> 

format( '%s' )
> %s

format( '%s:%s', 'a' )
> a:%s

However, if there are more arguments than expressions, qb-format-s will throw an error.