A simple Hydrator in JS (ES6)

Hydrator.js

"use strict";

class Hydrator
{
    #immutable;

    fromEntity;
    toEntity;

    constructor (fromEntity, toEntity, lazy = true, immutable = true)
    {
        this.fromEntity = fromEntity;
        this.toEntity = toEntity;

        this.immutable = !immutable;

        if (lazy) {
            this.toEntity = this.hydrate();
        }
    }

    hydrate()
    {
        for (const [name, value] of Object.entries(this.fromEntity)) {
            if (Object.hasOwn(this.toEntity, name)) {
                Object.defineProperty(this.toEntity, name, {
                    value: value,
                    writable: this.immutable
                });
            }
        }

        return this.toEntity;
    }
}