object-hasown-codemod.md

Object.hasOwn() codemod

We're looking for community feedback for the Object.hasOwn() TC39 proposal which is currently at Stage 3 and is being implemented in browsers.

If you successfully migrate your codebase to Object.hasOwn() please provide us with feedback even if its just a 👍

If you have any trouble with this codemod feel free to comment here.

Install the polyfill:

object.hasown

npm install object.hasown

Add it to your project:

import "object.hasown/auto"

// or

import hasOwn from "object.hasown"

if (!Object.hasOwn) {
	hasOwn.shim();
}

Run the codemod:

View Source • @codemod/cli docs

npx \
  -p @codemod/cli \
  codemod \
  --remote-plugin https://astexplorer.net/\#/gist/d5ceeb062688edbd8bee8e98967a94be/84b76a4dfd3f6e89ba388aa70f25d351dd5af309 \
  src # replace with your source directory

Before:

import has from "has"
import lodash from "lodash"
import lodashDotHas from "lodash.has"
import lodashSlashHas from "lodash/has"
import * as lodashEs from "lodash-es"
import {has as lodashEsHas} from "lodash-es"
import lodashEsSlashHas from "lodash-es/has"

has(obj, "prop")
lodash.has(obj, "prop")
lodashDotHas(obj, "prop")
lodashSlashHas(obj, "prop")
lodashEs.has(obj, "prop")
lodashEsHas(obj, "prop")
lodashEsSlashHas(obj, "prop")

After:

Object.hasOwn(obj, "prop");
Object.hasOwn(obj, "prop");
Object.hasOwn(obj, "prop");
Object.hasOwn(obj, "prop");
Object.hasOwn(obj, "prop");
Object.hasOwn(obj, "prop");
Object.hasOwn(obj, "prop");

Caveats

• This codemod does not support some lodash features like nested lodash.has(obj, "nested.properties")
• There are minor differences between these libraries and Object.hasOwn() (very few people should be affected by this)