error-cause/helpers/polyfill.js

An ES-spec-compliant shim/polyfill/replacement for the `.cause` property on all Error types that works as far down as ES3

'use strict';

module.exports = function polyfillHelper(C, implementation) {
	return function polyfill() {
		var options = { cause: { sentinel: true } };
		var e = new C('a', options);
		if (
			'cause' in e
			&& !('cause' in C.prototype) // https://bugs.chromium.org/p/v8/issues/detail?id=12006
			&& e.cause === options.cause
		) {
			return C;
		}
		return implementation;
	};
};