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https://github.com/villesau/optional-chaining-codemod
Codemod to migrate from Lodash get and logical and expressions to optional chaining
https://github.com/villesau/optional-chaining-codemod
codemod codemods es6 es7 javascript jscodeshift optional-chaining transform
Last synced: 2 days ago
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Codemod to migrate from Lodash get and logical and expressions to optional chaining
- Host: GitHub
- URL: https://github.com/villesau/optional-chaining-codemod
- Owner: villesau
- License: mit
- Created: 2018-10-28T21:45:13.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2023-03-04T04:15:28.000Z (almost 2 years ago)
- Last Synced: 2024-04-22T15:45:56.568Z (10 months ago)
- Topics: codemod, codemods, es6, es7, javascript, jscodeshift, optional-chaining, transform
- Language: JavaScript
- Size: 445 KB
- Stars: 112
- Watchers: 3
- Forks: 14
- Open Issues: 14
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
- awesome-codemods - optional-chaining-codemod - Codemod to migrate from Lodash get and logical and expressions to optional chaining. (Libraries / Lodash)
README
# Optional chaining codemod
[](https://travis-ci.org/villesau/optional-chaining-codemod)
[](https://www.npmjs.com/package/optional-chaining-codemod)
[](https://github.com/villesau/optional-chaining-codemod/blob/master/README.md#Contributing)
This is a codemod to migrate different types of lodash `get` calls and `a && a.b` kind of
expressions to use [optional chaining](https://github.com/tc39/proposal-optional-chaining)
and [nullish coalescing](https://github.com/tc39/proposal-nullish-coalescing) instead.
Following babel plugins are required to transpile optional chaining and nullish
coalescing:
- [babel-plugin-proposal-optional-chaining](https://babeljs.io/docs/en/babel-plugin-proposal-optional-chaining)
- [babel-plugin-proposal-nullish-coalescing-operator](https://babeljs.io/docs/en/babel-plugin-proposal-nullish-coalescing-operator)
## What it does?
- `a && a.b` becomes `a?.b`
- `_.get(foo, 'a.b')` and `_.get(foo, ['a', 'b'])` becomes `foo?.a?.b`
- `_.get(foo, 'a.b', defaultValue)` becomes `foo?.a?.b ?? defaultValue`
You can check out the [`__textfixtures__`](https://github.com/villesau/optional-chaining-codemod/tree/master/__testfixtures__) folder to see full list of supported transformations.
## Why should I migrate to use optional chaining?
- When using static type checkers like [Flow](https://github.com/facebook/flow) or Typescript,
optional chaining provides much better type safety than lodash `get`. Optional chaining is standard Javascript
feature.
- It also has a neater syntax than chaining `&&` expressions one after another.
## Install
```bash
$ yarn global add optional-chaining-codemod
```
or
```bash
$ npm install -g optional-chaining-codemod
```
## Usage
```bash
$ optional-chaining-codemod ./**/*.js --ignore-pattern="**/node_modules/**"
```
with flow parser:
```bash
$ optional-chaining-codemod ./**/*.js --ignore-pattern="**/node_modules/**" --parser=flow
```
with typescript parser:
```bash
$ optional-chaining-codemod ./**/*.ts --ignore-pattern="**/node_modules/**" --parser=ts
```
with typescript+react parser:
```bash
$ optional-chaining-codemod ./**/*.tsx --parser=tsx
```
The CLI is the same as in [jscodeshift](https://github.com/facebook/jscodeshift)
except you can omit the transform file.
Alternatively, you can run the codemod using jscodeshift as follows:
```bash
$ yarn global add jscodeshift
$ yarn add optional-chaining-codemod
$ jscodeshift -t node_modules/optional-chaining-codemod/transform.js --ignore-pattern="**/node_modules/**" ./**/*.js
```
### flags
This codemod has two flags:
1. `--skipVariables` to skip variables passed to lodash `get`
2. `--skipTemplateStrings` to skip template strings passed to lodash `get`
Especially the first case is risky as the variable might actually be something
like `var bar = "a.b.c"` and produce from `_.get(foo, bar)` following: `foo?[bar]` although lodash would treat it like `foo?.a?.b?.c"`.
## Contributing
Contributions are more than welcome! One area of improvement could be e.g
better CLI or finding out new areas to migrate to use optional chaining.