typescript1.7 - Typescript: Pass an extra parameter -

i trying below code documentation

interface point {       x: number;       y: number;   }  function getx(p: point) {       return p.x;   }  class cpoint {       x: number;       y: number;       constructor(x: number,  y: number) {           this.x = x;           this.y = y;       }   }  getx(new cpoint(0, 0));  // ok, fields match  getx({ x: 0, y: 0, color: "red" });  // fields ok  getx({ x: 0 });  // error: supplied parameter not match 

as per code comment says below line should ok.

getx({ x: 0, y: 0, color: "red" });  // fields ok 

but getting error below:

error ts2345: argument of type '{ x: number; y: number; color: string; }' not assignable parameter of type 'point'. object literal may specify known properties, , 'color' not exist in type 'point'

but below code works re-wrote in made params optional:

interface point {       x: number;       y?: number;      color?: string;  }  function getx(p: point) {       return p.x;   }  class cpoint {       x: number;       y: number;       constructor(x: number,  y: number) {           this.x = x;           this.y = y;       }   }  getx(new cpoint(0, 0));  // ok, fields match  getx({ x: 0, y: 0, color: "red" });  // fields ok  getx({ x: 0 });  // error: supplied parameter not match 

please can me out if documentation wrong or missing here

fyi using:

• typescript v1.7.5
• visual studio code

screenshot:

the documentation out of date. used ok add property, in typescript 1.6 changed behaviour.

if want work in ts 1.6+ have type assertion:

getx({ x: 0, y: 0, color: "red" } point); // no error