Object.create isn't a direct clone - it's a prototype assignment

demo.ts

 class Foo {                                                                                   
    constructor(public bar: string) { }                                                         
 }                                                                                             
 
 let f1 = new Foo('demovalue');                                                                
 let f2 = Object.create(f1);                                                                   
 console.log(`f1 = ${JSON.stringify(f1)}`);                                                    
 console.log(`f2 = ${JSON.stringify(f2)}`);                                                    
 
 f1.bar = 'changed';                                                                           
 console.log(`changed f1.bar to "changed"`);                                                   
 console.log(`f1 = ${JSON.stringify(f1)}`);                                                    
 console.log(`f2 = ${JSON.stringify(f2)}`);                                                    

 f2.bar = 'changed f2';                                                                        
 f1.bar = 'changed f1';                                                                        
 
 console.log(`overwrote f2.bar and then updated f1.bar`);                                      
 console.log(`f1 = ${JSON.stringify(f1)}`);                                                    
 console.log(`f2 = ${JSON.stringify(f2)}`);                                                    
 
 console.log('moral of the story - understand Object.create is just setting a prototype');     

output.txt

// after running tsc demo.ts, and then node demo.js
> node demo.js
f1 = {"bar":"demovalue"}
f2 = {}   // f2's __proto__ property is f1
changed f1.bar to "changed"
f1 = {"bar":"changed"}
f2 = {}  // f2 does not override f1's bar property
overwrote f2.bar and then updated f1.bar
f1 = {"bar":"changed f1"}
f2 = {"bar":"changed f2"}  // now we have an overridden bar property in the child 
moral of the story - understand Object.create is just setting a prototype, NOT cloning directly.