function enable(namespaces) {
		createDebug.save(namespaces);
		createDebug.namespaces = namespaces;

		createDebug.names = [];
		createDebug.skips = [];

		let i;
		const split = (typeof namespaces === 'string' ? namespaces : '').split(/[\s,]+/);
		const len = split.length;

		for (i = 0; i < len; i++) {
			if (!split[i]) {
				// ignore empty strings
				continue;
			}

			namespaces = split[i].replace(/\*/g, '.*?');

			if (namespaces[0] === '-') {
				createDebug.skips.push(new RegExp('^' + namespaces.substr(1) + '$'));
			} else {
				createDebug.names.push(new RegExp('^' + namespaces + '$'));
			}
		}
	}
Enables a debug mode by namespaces. This can include modes
separated by a colon and wildcards.

@param {String} namespaces
@api public