ast-walker-scope

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[![npm downloads][npm-downloads-src]][npm-downloads-href]
[![Unit Test][unit-test-src]][unit-test-href]

Traverse Babel AST with scope information.

Inherited from estree-walker.

Install

``bash
npm i ast-walker-scope
`

Usage

$3

For a real example, you can refer to example.ts

`ts
import { walk } from 'ast-walker-scope'

const code =
const a = 'root level'

{
const a = 'second level'
let secondLevel = true
console.log(a, secondLevel)
}

var err = undefined
try {
} catch (err) {
console.log(err)
}

console.log(a)
.trim()

walk(code, {
leave(this, node) {
if (node.type === 'CallExpression') {
console.log(\nLevel: ${this.level})
for (const [name, node] of Object.entries(this.scope)) {
console.log(
variable ${name} is located at line ${node.loc?.start.line}, column ${node.loc?.start.column},
)
}
}
},
})
`

Output:

`
Level: 2
variable a is located at line 4, column 8
variable secondLevel is located at line 5, column 6

Level: 2
variable a is located at line 1, column 6
variable err is located at line 12, column 9

Level: 1
variable a is located at line 1, column 6
variable err is located at line 9, column 4
`

Typings

`ts
export type Scope = Record
export interface HookContext extends WalkerContext {
// inherited from estree-walker
skip: () => void
remove: () => void
replace: (node: Node) => void

// arguments of estree-walker hook
parent: Node
key: string
index: number

// scope info
scope: Scope
scopes: Scope[]
level: number
}
``

Sponsors

Credits

- @vue/reactivity-transform - almost copy-like referenced

License

MIT License © 2022-PRESENT 三咲智子

[npm-version-src]: https://img.shields.io/npm/v/ast-walker-scope.svg
[npm-version-href]: https://npmjs.com/package/ast-walker-scope
[npm-downloads-src]: https://img.shields.io/npm/dm/ast-walker-scope
[npm-downloads-href]: https://www.npmcharts.com/compare/ast-walker-scope?interval=30
[unit-test-src]: https://github.com/sxzz/ast-walker-scope/actions/workflows/unit-test.yml/badge.svg
[unit-test-href]: https://github.com/sxzz/ast-walker-scope/actions/workflows/unit-test.yml