Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/tusharmath/ts-codemod
Typescript based codemods
https://github.com/tusharmath/ts-codemod
Last synced: 6 days ago
JSON representation
Typescript based codemods
- Host: GitHub
- URL: https://github.com/tusharmath/ts-codemod
- Owner: tusharmath
- Created: 2018-07-13T17:46:42.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2019-11-07T07:05:49.000Z (about 5 years ago)
- Last Synced: 2024-08-08T20:41:52.994Z (3 months ago)
- Language: TypeScript
- Homepage:
- Size: 411 KB
- Stars: 69
- Watchers: 3
- Forks: 10
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
- awesome-codemods - ts-codemod - Typescript based codemods. (Typescript)
README
# ts-codemod
[](https://travis-ci.com/tusharmath/ts-codemod)
Code-Modifier for Typescript based projects.
## Index
- [Installation](#installation)
- [Command Line Usage](#command-line-usage)
- [Example](#example)
- [Custom Transformation](#custom-transformation)
- [Post Transformation](#post-transformation)
- [Builtin Transformations](https://github.com/tusharmath/ts-codemod/blob/master/CODEMOD.md)
## Installation
```bash
npm i -g ts-codemod
```
## Command Line Usage
A typical command looks like -
```bash
ts-codemod --transformation [transformation name] --params [transformation params] --write [glob pattern]
```
| **Argument** | **Purpose** | **Value** |
| ------------------------------------ | --------------------------------------- | --------- |
| `--write` `-w` (_optional_) | Writes back to the file | `false` |
| `--transformation` `-t` (_required_) | Name of the transformation or file path | |
| `--params` `-p` ( _optional_) | Additional transformation specific args | |
## Example
So lets say I want to update the import statements throughout the application from something like —
```ts
import * as components from '../../../component'
```
to something like —
```ts
import * as components from 'component'
```
Here I have removed the unnecessary `../../../` from the import statement. To achieve this goal I can use the [normalize-import-path] transformation.
1. Create a `.tscodemodrc` file
```json5
{
// name of the transformation
transformation: 'normalize-import-path',
// transformation params
params: {
module: 'component'
}
}
```
2. Run the code mod.
```bash
ts-codemod --write src/**/*.ts
```
Alternatively you can also pass all the arguments without creating a `.tscodemodrc` file —
```bash
ts-codemod --transformation normalize-import-path --params.module=component --write src/**/*.ts
```
## Custom transformation
Writing a custom transformation isn't very easy and one needs to understand how typescript internally converts plain string to an AST.
A good starter could be to checkout the [transformations] directory. Those transformations are written for a varied level of complexity. Also checkout the [AST Explorer](https://astexplorer.net/) website to get an understanding of ASTs in general.
A custom transformation (`my-custom-transformation.ts`) can be implemented via extending the `Transformation` class.
```ts
import * as ts from 'typescript'
import {Transformation} from 'ts-codemod'
// my-custom-transformation.ts
export default class MyCustomTransformation extends Transformation {
visit(node: ts.Node): ts.VisitResult {
// write your implementation here
return node // will apply no-change
}
}
```
It can then be executed as —
```bash
ts-codemod -t ./my-custom-transformation.ts src/**.ts
```
**Passing Custom Params:**
To pass custom params to your transformation can be done as follows —
```ts
export type MyParams = {
moduleName: string
}
// my-custom-transformation.ts
export default class MyCustomTransformation extends Transformation {
// Called before the transformation is applied on the file
before () {
}
visit(node: ts.Node): ts.VisitResult {
// access the params
console.log(this.params.moduleName)
...
}
// Called after the transformation is applied on the file
after () {
}
}
```
The additional params are passed via the `--params.moduleName` cli argument or if you are using a `.tscodemodrc` file —
```json5
{
params: {
moduleName: 'abc'
}
}
```
## Post Transformation
1. Life can't be that simple right? Running transformations will generally ruin the formatting of your files. A recommended way to solve that problem is by using [Prettier].
2. Even after running prettier its possible to have unnecessary new lines added/removed. This can be solved by ignoring white spaces while staging the changes in `git`.
```bash
git diff --ignore-blank-lines | git apply --cached
```
[prettier]: https://prettier.io