Traverse Babel AST with scope information.
Inherited from estree-walker.
npm i ast-walker-scopeFor a real example, you can refer to example.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
export type Scope = Record<string, Node>
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
}
- @vue/reactivity-transform - almost copy-like referenced