extsprintf: extended POSIX-style sprintf¶ ↑
Stripped down version of sprintf(3c). We make a best effort to throw an exception when given a format string we don't understand, rather than ignoring it, so that we won't break existing programs if/when we go implement the rest of this.
This implementation currently supports specifying
-
field alignment ('-' flag),
-
zero-pad ('0' flag)
-
always show numeric sign ('+' flag),
-
field width
-
conversions for strings, decimal integers, and floats (numbers).
-
argument size specifiers. These are all accepted but ignored, since Javascript has no notion of the physical size of an argument.
Everything else is currently unsupported, most notably: precision, unsigned numbers, non-decimal numbers, and characters.
Besides the usual POSIX conversions, this implementation supports:
-
%j
: pretty-print a JSON object (using node's “inspect”) -
%r
: pretty-print an Error object
Example¶ ↑
First, install it:
# npm install extsprintf
Now, use it:
var mod_extsprintf = require('extsprintf'); console.log(mod_extsprintf.sprintf('hello %25s', 'world'));
outputs:
hello world