JS: Array.from that works without .length

index.js

/**
 * Converts an array-like object into an array.
 * Array.from doesn't work if an object doesn't have a "length" property.
 * e.g., Array.from({ 0: 1 }) doesn't work; Array.from({ 0: 1, length: 1 }) does.
 */
function arrayFrom (obj: {}): Array<*> {
    return Object.keys(obj).reduce((set: Array, key: string) => {
        return [...set, obj[key]]
    }, [])
}