src/vs/editor/common/languages/supports/onEnter.ts/OnEnterSupport/constructor
class OnEnterSupport:	constructor(opts: IOnEnterSupportOptions) {
		opts = opts || {};
		opts.brackets = opts.brackets || [
			['(', ')'],
			['{', '}'],
			['[', ']']
		];

		this._brackets = [];
		opts.brackets.forEach((bracket) => {
			const openRegExp = OnEnterSupport._createOpenBracketRegExp(bracket[0]);
			const closeRegExp = OnEnterSupport._createCloseBracketRegExp(bracket[1]);
			if (openRegExp && closeRegExp) {
				this._brackets.push({
					open: bracket[0],
					openRegExp: openRegExp,
					close: bracket[1],
					closeRegExp: closeRegExp,
				});
			}
		});
		this._regExpRules = opts.onEnterRules || [];
	}