cassert

C-style assertions for javascript and coffee-script, running in node.js. Extracts assertion failure messages from the expressions themselves. Based on better-assert.

Installation

npm install cassert

Usage

Require the module and use it as an assert function, just as you would in C. As long as the NODE_ENV environment variable is not set to production, cassert will perform the check. Note that for coffee-script, the assert failure message will show the compiled javascript expression.

Important: The assert function must be invoked as assert(expression), cassert(expression), or similar name ending on assert.

Javascript Example

var assert = require('cassert');

function foo(bar) {
    assert(typeof bar === 'number');
    assert(bar > 10);
}

foo(5);

AssertionError: bar > 10
    at foo (d:\git\cassert\test.js:5:5)
    at Object.<anonymous> (d:\git\cassert\test.js:8:1)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.runMain (module.js:492:10)
    at process.startup.processNextTick.process._tickCallback (node.js:244:9)

CoffeeScript Example

assert = require 'cassert'

foo = (bar) ->
    assert typeof bar is 'number'
    assert bar > 10

foo 5

AssertionError: bar > 10
    at foo (d:\git\cassert\test.coffee:8:12)
    at Object.<anonymous> (d:\git\cassert\test.coffee:11:3)
    at Object.<anonymous> (d:\git\cassert\test.coffee:13:4)
    at Module._compile (module.js:449:26)
    at Object.exports.run (c:\Users\Johan\AppData\Roaming\npm\node_modules\coffee-script\lib\coffee-script\coffee-script.js:83:25)
    at compileScript (c:\Users\Johan\AppData\Roaming\npm\node_modules\coffee-script\lib\coffee-script\command.js:177:29)
    at fs.stat.notSources.(anonymous function) (c:\Users\Johan\AppData\Roaming\npm\node_modules\coffee-script\lib\coffee-script\command.js:152:18)
    at fs.readFile (fs.js:176:14)
    at Object.oncomplete (fs.js:297:15)

License (BSD)

Copyright (c) 2013, Johan Sköld <[email protected]>
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.