eslint/docs/src/rules/no-proto.md

   1 ---
   2 title: no-proto
   3 rule_type: suggestion
   4 further_reading:
   5 - https://johnresig.com/blog/objectgetprototypeof/
   6 ---
   7
   8
   9 `__proto__` property has been deprecated as of ECMAScript 3.1 and shouldn't be used in the code. Use `Object.getPrototypeOf` and `Object.setPrototypeOf` instead.
  10
  11 ## Rule Details
  12
  13 When an object is created with the `new` operator, `__proto__` is set to the original "prototype" property of the object's constructor function. `Object.getPrototypeOf` is the preferred method of getting the object's prototype. To change an object's prototype, use `Object.setPrototypeOf`.
  14
  15 Examples of **incorrect** code for this rule:
  16
  17 ::: incorrect
  18
  19 ```js
  20 /*eslint no-proto: "error"*/
  21
  22 var a = obj.__proto__;
  23
  24 var a = obj["__proto__"];
  25
  26 obj.__proto__ = b;
  27
  28 obj["__proto__"] = b;
  29 ```
  30
  31 :::
  32
  33 Examples of **correct** code for this rule:
  34
  35 ::: correct
  36
  37 ```js
  38 /*eslint no-proto: "error"*/
  39
  40 var a = Object.getPrototypeOf(obj);
  41
  42 Object.setPrototypeOf(obj, b);
  43
  44 var c = { __proto__: a };
  45 ```
  46
  47 :::
  48
  49 ## When Not To Use It
  50
  51 You might want to turn this rule off if you need to support legacy browsers which implement the
  52 `__proto__` property but not `Object.getPrototypeOf` or `Object.setPrototypeOf`.