Promise.allSettled polyfill

promise-proto.js

if (!Promise.allSettled) {
    // Polyfill
    Promise.prototype.allSettled = function(values) {
        if (this == null) {
            throw new TypeError('this is null or not defined');
        }

        return this.all(values.map(reflect));
    };

    function reflect(promise) {
        return promise.then(
            (v) => {
                return { status: 'fulfilled', value: v };
            },
            (error) => {
                return { status: 'rejected', reason: error };
            }
        );
    }
}