Making a data type that can support building a schema with both required and not required fields

data_type.es6

export default class DataType {
    constructor(name){
        this._name = name;
        this._fields = {}
        this.createDataSet = data => {
            var newData = {}
            Object.keys(this._fields).forEach(key => {
                ({ [key]: newData[key] = this._fields[key]() } = data);
            })
            return newData
        }
    }
    setField(name, type){
        this._fields[name] = () => ''
    }
    setRequiredField(name, type){
        this._fields[name] = () => { throw new Error(`missing ${name}`) }
    }
}