catchall

Catch all javascript exceptions

npm install catchall
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Motivation

  • better alternative to window.onerror. Actually catches all exceptions thrown in JavaScript.
  • Catch errors where they originate from.
  • Ability to send errors to a server while alpha testing.
  • Insipired by proxino.

Super Important Note

All function bodies are wrapped in try-catch blocks, so it would be a terrible idea to use this for production code.

Example

Create a file called script.js:


//only catch all if functions have been wrapped around
if(typeof catchall != 'undefined') {

    //on catch all, send error to server
    catchall.error = function(e) {
        console.error('An error has occurred!');
        console.error(e.message);
    }    
}


function badFunction() {
    unknownFunction();
}

badFunction();

In terminal, type:

catchall -i ./script.js -o ./script.guarded.js
node ./script.guarded.js

The message you should see is:

An error has occurred!
unknownFunction is not defined

Command Line Usage

Usage: -i [input_js]

Options:
  -i, --input   input js file or url  [required]
  -o, --output  output js file

Connect Middleware

var catchall = require('catchall'),
connect = require('connect'),
app = connect.createServer();
app.use(catchall.connectMiddleware);
app.use(connect.static(__dirname + '/public'));
app.listen(8080);

Test it out by typing this into your browser: http://localhost:8080/catchall/http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.js

API

catchall.wrap(source[, ops], callback)

Generates guarded code where all exceptions are caught.

  • source - the javascript source to wrap around.
  • ops - the wrap options.
    • addHandler - add the handler at the head of the script (catchall.error = function(){})

Here's a simple example:


var catchall = require('catchall');

catchall.wrap('function test(){ notDefined(); }', function(err, wrappedSource) {
    //do stuff
});

The above script will produce:

function test() {
    try {
        notDefined();
    } catch(e) {
        catchall.error(e);
    }
}

catchall.load(source, callback)

Loads the given source, and wraps around it. Can be from fs, or url.

Example:

catchall.load('http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.js', function(err, result) {
    //do something
});

catchall.load('/from/fs', function(err, result) {
    //do something
});
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