forked from lix-project/lix-website
99 lines
2.7 KiB
Markdown
99 lines
2.7 KiB
Markdown
|
# eslint-visitor-keys
|
||
|
|
|
||
|
|
[](https://www.npmjs.com/package/eslint-visitor-keys)
|
||
|
|
[](http://www.npmtrends.com/eslint-visitor-keys)
|
||
|
|
[](https://travis-ci.org/eslint/eslint-visitor-keys)
|
||
|
|
[](https://david-dm.org/eslint/eslint-visitor-keys)
|
||
|
|
|
||
|
|
Constants and utilities about visitor keys to traverse AST.
|
||
|
|
|
||
|
|
## 💿 Installation
|
||
|
|
|
||
|
|
Use [npm] to install.
|
||
|
|
|
||
|
|
```bash
|
||
|
|
$ npm install eslint-visitor-keys
|
||
|
|
```
|
||
|
|
|
||
|
|
### Requirements
|
||
|
|
|
||
|
|
- [Node.js] 10.0.0 or later.
|
||
|
|
|
||
|
|
## 📖 Usage
|
||
|
|
|
||
|
|
```js
|
||
|
|
const evk = require("eslint-visitor-keys")
|
||
|
|
```
|
||
|
|
|
||
|
|
### evk.KEYS
|
||
|
|
|
||
|
|
> type: `{ [type: string]: string[] | undefined }`
|
||
|
|
|
||
|
|
Visitor keys. This keys are frozen.
|
||
|
|
|
||
|
|
This is an object. Keys are the type of [ESTree] nodes. Their values are an array of property names which have child nodes.
|
||
|
|
|
||
|
|
For example:
|
||
|
|
|
||
|
|
```
|
||
|
|
console.log(evk.KEYS.AssignmentExpression) // → ["left", "right"]
|
||
|
|
```
|
||
|
|
|
||
|
|
### evk.getKeys(node)
|
||
|
|
|
||
|
|
> type: `(node: object) => string[]`
|
||
|
|
|
||
|
|
Get the visitor keys of a given AST node.
|
||
|
|
|
||
|
|
This is similar to `Object.keys(node)` of ES Standard, but some keys are excluded: `parent`, `leadingComments`, `trailingComments`, and names which start with `_`.
|
||
|
|
|
||
|
|
This will be used to traverse unknown nodes.
|
||
|
|
|
||
|
|
For example:
|
||
|
|
|
||
|
|
```
|
||
|
|
const node = {
|
||
|
|
type: "AssignmentExpression",
|
||
|
|
left: { type: "Identifier", name: "foo" },
|
||
|
|
right: { type: "Literal", value: 0 }
|
||
|
|
}
|
||
|
|
console.log(evk.getKeys(node)) // → ["type", "left", "right"]
|
||
|
|
```
|
||
|
|
|
||
|
|
### evk.unionWith(additionalKeys)
|
||
|
|
|
||
|
|
> type: `(additionalKeys: object) => { [type: string]: string[] | undefined }`
|
||
|
|
|
||
|
|
Make the union set with `evk.KEYS` and the given keys.
|
||
|
|
|
||
|
|
- The order of keys is, `additionalKeys` is at first, then `evk.KEYS` is concatenated after that.
|
||
|
|
- It removes duplicated keys as keeping the first one.
|
||
|
|
|
||
|
|
For example:
|
||
|
|
|
||
|
|
```
|
||
|
|
console.log(evk.unionWith({
|
||
|
|
MethodDefinition: ["decorators"]
|
||
|
|
})) // → { ..., MethodDefinition: ["decorators", "key", "value"], ... }
|
||
|
|
```
|
||
|
|
|
||
|
|
## 📰 Change log
|
||
|
|
|
||
|
|
See [GitHub releases](https://github.com/eslint/eslint-visitor-keys/releases).
|
||
|
|
|
||
|
|
## 🍻 Contributing
|
||
|
|
|
||
|
|
Welcome. See [ESLint contribution guidelines](https://eslint.org/docs/developer-guide/contributing/).
|
||
|
|
|
||
|
|
### Development commands
|
||
|
|
|
||
|
|
- `npm test` runs tests and measures code coverage.
|
||
|
|
- `npm run lint` checks source codes with ESLint.
|
||
|
|
- `npm run coverage` opens the code coverage report of the previous test with your default browser.
|
||
|
|
- `npm run release` publishes this package to [npm] registory.
|
||
|
|
|
||
|
|
|
||
|
|
[npm]: https://www.npmjs.com/
|
||
|
|
[Node.js]: https://nodejs.org/en/
|
||
|
|
[ESTree]: https://github.com/estree/estree
|