debug/debug.js
Nathan Rajlich 61394bf18e debug: use "ms" module for humanizing the diff
This would be the first external dependency for `debug`,
so it's slightly controversial.
2014-05-31 13:24:29 -07:00

121 lines
2.2 KiB
JavaScript

/**
* This is the common logic for both the Node.js and web browser
* implementations of `debug()`.
*
* Expose `debug()` as the module.
*/
exports = module.exports = debug;
exports.coerce = coerce;
exports.disable = disable;
exports.enable = enable;
exports.enabled = enabled;
exports.humanize = require('ms');
/**
* The currently active debug mode names, and names to skip.
*/
exports.names = [];
exports.skips = [];
/**
* Create a debugger with the given `namespace`.
*
* @param {String} namespace
* @return {Function}
* @api public
*/
function debug(namespace) {
// define the `disabled` version
function disabled() {
}
disabled.enabled = false;
// define the `enabled` version
function enabled(fmt) {
fmt = exports.coerce(fmt);
exports.log.apply(enabled, arguments);
}
enabled.enabled = true;
var fn = exports.enabled(namespace) ? enabled : disabled;
fn.namespace = namespace;
return fn;
}
/**
* Enables a debug mode by namespaces. This can include modes
* separated by a colon and wildcards.
*
* @param {String} namespaces
* @api public
*/
function enable(namespaces) {
exports.save(namespaces);
var split = (namespaces || '').split(/[\s,]+/);
var len = split.length;
for (var i = 0; i < len; i++) {
namespaces = split[i].replace('*', '.*?');
if (namespaces[0] === '-') {
exports.skips.push(new RegExp('^' + namespaces.substr(1) + '$'));
} else {
exports.names.push(new RegExp('^' + namespaces + '$'));
}
}
}
/**
* Disable debug output.
*
* @api public
*/
function disable() {
exports.enable('');
}
/**
* Returns true if the given mode name is enabled, false otherwise.
*
* @param {String} name
* @return {Boolean}
* @api public
*/
function enabled(name) {
var i, len;
for (i = 0, len = exports.skips.length; i < len; i++) {
if (exports.skips[i].test(name)) {
return false;
}
}
for (i = 0, len = exports.names.length; i < len; i++) {
if (exports.names[i].test(name)) {
return true;
}
}
return false;
}
/**
* Coerce `val`.
*
* @param {Mixed} val
* @return {Mixed}
* @api private
*/
function coerce(val) {
if (val instanceof Error) return val.stack || val.message;
return val;
}