Package Exports

verror

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (verror) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

verror: richer JavaScript errors

This module provides VError, which is like JavaScript's built-in Error class, but supports a "cause" argument and a printf-style message. The cause argument can be null. For example:

if (err)
    throw (new VError(err, 'operation "%s" failed', opname));

If err.message is "file not found" and "opname" is "rm", then the thrown exception's toString() would return:

   operation "rm" failed: file not found

This is useful for annotating exceptions up the stack, rather than getting an extremely low-level error (like "file not found") for a potentially much higher level operation.

Additionally, when printed using node-extsprintf using %r, each exception's stack is printed.

Example

First, install it:

# npm install verror

Now, use it:

var mod_fs = require('fs');
var mod_extsprintf = require('extsprintf');
var mod_verror = require('../lib/verror');

mod_fs.stat('/nonexistent', function (err) {
    console.log(mod_extsprintf.sprintf('%r',
        new mod_verror.VError(err, 'operation failed')));
});

outputs:

EXCEPTION: VError: operation failed: ENOENT, no such file or directory '/nonexistent'
    at Object.oncomplete (/home/dap/node-verror/examples/simple.js:7:6)
Caused by: EXCEPTION: Error: Error: ENOENT, no such file or directory '/nonexistent'