JS: Create Object with Parent X

By Xah Lee. Date: . Last updated: .

Here's how to create a object with a specified parent object.

Object Literal Expression

obj = { __proto__:my_parent, k1 = v1, k2 = v2, … }

const e1 = {p:7};

// create object with e1 as parent, and a property x
const e2 = {__proto__:e1, x:8};

console.log( e2 ); // { x: 8 };

console.log (
    Object.getPrototypeOf ( e2 ) === e1
); // true

[see JS: Object.prototype.__proto__]


obj = Object.Create(my_parent)

[see JS: Object.create]

With Constructor

Use a constructor, by the following steps:

  1. Define a function F with no return statement.
  2. Set the prototype property: F.prototype = my_parent
  3. Create the object. const obj = new F.

[see JS: Operator “new”]

With keyword “class”

  1. Define a class named X. (the constructor should not contain return statement.)
  2. JavaScript will create a object X.prototype.
  3. new X(…)'s parent is X.prototype

[see JS: Class]

JS Object and Inheritance

  1. Object Overview
  2. Object Type
  3. Find Object's Type
  4. Prototype Chain
  5. Create Object
  6. Object Literal Expr
  7. Create Object with Parent X
  8. Get/Set Parent
  9. Show Prototype Chain
  10. Prevent Adding Property
  11. Clone Object
  12. Test Object Equality
  13. Add Method to Prototype

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