throw

You can't use throw statement in expressions in JavaScript:

arg = arg || throw new Error('arg is required');
// => SyntaxError: Unexpected token throw

This tiny library is wrapping throw in a function:

var thr = require('throw');

// ...

arg = arg || thr('arg is required');

Messages can contain printf-like placeholders:

arg = arg || thr('"%s" is required', argName);

You can specify instance of Error instead of message:

arg = arg || thr(new Error('arg is required'));

Or parametrize error class:

arg = arg || thr(Error, 'arg is required');

Installation

$ npm install --save throw

var thr = require('throw');

var parsed = parse(str) || thr('Could not parse "%s"', str);

MIT