add throwing of AssertionError for test frameworks etc

Readme.md

@@ -1,38 +1,48 @@
 
 # better-assert
 
-  Better in-application assertions for node, reporting the expr, filename, lineno etc using [callsite](https://github.com/visionmedia/callsite).
+  Better c-style assertions using [callsite](https://github.com/visionmedia/callsite) for
+  self-documenting failure messages.
 
 ## Installation
 
     $ npm install better-assert
 
 ## Example
 
- By default assertions are disabled, so the calls to `assert()` will simply be ignored. Use the __ASSERT__ env var to enable:
+ By default assertions are enabled, however the __NO_ASSERT__ environment variable 
+ will deactivate them when truthy.
 
 ```js
 var assert = require('better-assert');
 
-var user = { authenticated: false };
-assert(user.authenticated);
 
-user.authenticated = true;
-assert(user.authenticated);
+var assert = require('./');
 
-user.authenticated = 0;
-assert(user.authenticated);
-```
+test();
 
-outputting:
+function test() {
+  var user = { name: 'tobi' };
+  assert('tobi' == user.name);
+  assert('number' == typeof user.age);
+}
 
-![assertions](http://f.cl.ly/items/1F1W0H0h2T0L233L352o/Screenshot.png)
+AssertionError: 'number' == typeof user.age
+    at test (/Users/tj/projects/better-assert/example.js:9:3)
+    at Object.<anonymous> (/Users/tj/projects/better-assert/example.js:4:1)
+    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)
+```
 
 ## License 
 
 (The MIT License)
 
-Copyright (c) 2011 TJ Holowaychuk &lt;tj@vision-media.ca&gt;
+Copyright (c) 2012 TJ Holowaychuk &lt;tj@vision-media.ca&gt;
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the

example.js

@@ -1,13 +1,10 @@
 
 var assert = require('./');
 
-assert('wahoo');
+test();
 
-var user = { authenticated: false };
-assert(user.authenticated);
-
-user.authenticated = true;
-assert(user.authenticated);
-
-user.authenticated = 0;
-assert(user.authenticated);
+function test() {
+  var user = { name: 'tobi' };
+  assert('tobi' == user.name);
+  assert('number' == typeof user.age);
+}

index.js

@@ -1,2 +1,39 @@
 
-module.exports = require('./lib/better-assert');
+/**
+ * Module dependencies.
+ */
+
+var AssertionError = require('assert').AssertionError
+  , callsite = require('callsite')
+  , fs = require('fs')
+
+/**
+ * Expose `assert`.
+ */
+
+module.exports = process.env.NO_ASSERT
+  ? function(){}
+  : assert;
+
+/**
+ * Assert the given `expr`.
+ */
+
+function assert(expr) {
+  if (expr) return;
+
+  var stack = __stack;
+  var call = stack[1];
+  var file = call.getFileName();
+  var lineno = call.getLineNumber();
+  var src = fs.readFileSync(file, 'utf8');
+  var line = src.split('\n')[lineno-1];
+  var src = line.match(/assert\((.*)\)/)[1];
+
+  var err = new AssertionError({
+    message: src,
+    stackStartFunction: stack[0].fun
+  });
+
+  throw err;
+}