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https://github.com/goto-bus-stop/scope-analyzer
simple scope analysis for javascript ASTs
https://github.com/goto-bus-stop/scope-analyzer
ast javascript variables
Last synced: 13 days ago
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simple scope analysis for javascript ASTs
- Host: GitHub
- URL: https://github.com/goto-bus-stop/scope-analyzer
- Owner: goto-bus-stop
- License: other
- Created: 2017-11-15T17:16:41.000Z (almost 7 years ago)
- Default Branch: default
- Last Pushed: 2022-12-12T04:03:15.000Z (almost 2 years ago)
- Last Synced: 2024-10-24T16:25:48.271Z (20 days ago)
- Topics: ast, javascript, variables
- Language: JavaScript
- Size: 70.3 KB
- Stars: 22
- Watchers: 2
- Forks: 7
- Open Issues: 7
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.md
Awesome Lists containing this project
README
# scope-analyzer
simple scope analysis for javascript ASTs. tracks scopes and collects references to variables.
Caveats and/or todos:
- May be missing edge cases.
- Things like `label:`s are not considered at all, but ideally in the future they will!
[![stability][stability-image]][stability-url]
[![npm][npm-image]][npm-url]
[![travis][travis-image]][travis-url]
[![standard][standard-image]][standard-url]
[stability-image]: https://img.shields.io/badge/stability-experimental-orange.svg?style=flat-square
[stability-url]: https://nodejs.org/api/documentation.html#documentation_stability_index
[npm-image]: https://img.shields.io/npm/v/scope-analyzer.svg?style=flat-square
[npm-url]: https://www.npmjs.com/package/scope-analyzer
[travis-image]: https://img.shields.io/travis/goto-bus-stop/scope-analyzer.svg?style=flat-square
[travis-url]: https://travis-ci.org/goto-bus-stop/scope-analyzer
[standard-image]: https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat-square
[standard-url]: http://npm.im/standard
## Install
```
npm install scope-analyzer
```
## Usage
Note: AST nodes passed to `scope-analyzer` functions are expected to reference the parent node on a `node.parent` property.
Nodes from [falafel](https://github.com/substack/node-falafel) or [transform-ast](https://github.com/goto-bus-stop/transform-ast) have a `.parent` property, but others may not. You can use [estree-assign-parent](https://github.com/goto-bus-stop/estree-assign-parent) to quickly assign a parent property to all nodes in an AST.
```js
var scan = require('scope-analyzer')
var ast = parse('...')
// Initialize node module variables
scan.createScope(ast, ['module', 'exports', '__dirname', '__filename'])
scan.crawl(ast)
var binding = scan.getBinding(ast, 'exports')
binding.getReferences().forEach(function (reference) {
// Assume for the sake of the example that all references to `exports` are assignments like
// `exports.xyz = abc`
console.log('found export:', reference.parent.property.name)
})
```
## API
### `crawl(ast)`
Walk the ast and analyze all scopes. This will immediately allow you to use the `get*` methods on any node in the tree.
### `clear(ast)`
Clear scope information in all nodes of the AST.
### `visitScope(node)`
Visit a node to check if it initialises any scopes.
For example, a function declaration will initialise a new scope to hold bindings for its parameters.
Use this if you are already walking the AST manually, and if you don't need the scope information during this walk.
### `visitBinding(node)`
Visit a node to check if it is a reference to an existing binding.
If it is, the reference is added to the parent scope.
Use this if you are already walking the AST manually.
### `createScope(node, bindings)`
Initialise a new scope at the given node. `bindings` is an array of variable names.
This can be useful to make the scope analyzer aware of preexisting global variables.
In that case, call `createScope` on the root node with the names of globals:
```js
var ast = parse('xyz')
scopeAnalyzer.createScope(ast, ['HTMLElement', 'Notification', ...])
```
### `deleteScope(node)`
Delete the scope initialised by node.
### `scope(node)`
Get the [Scope](#scope) initialised by the given node.
### `getBinding(node)`
Get the [Binding](#binding) referenced by the `Identifier` `node`.
### Scope
#### `scope.has(name)`
Check if this scope defines `name`.
#### `scope.getBinding(name)`
Get the [Binding](#binding) named `name` that is declared by this scope.
#### `scope.getReferences(name)`
Get a list of all nodes referencing the `name` binding that is declared by this scope.
#### `scope.getUndeclaredNames()`
Get a list of all names that were used in this scope, but not defined anywhere in the AST.
#### `scope.forEach(cb(binding, name))`
Loop over all bindings declared by this scope.
#### `scope.forEachAvailable(cb(binding, name))`
Loop over all bindings available to this scope, declared in this scope or any parent scope.
### Binding
#### `binding.definition`
The node that defined this binding. If this binding was not declared in the AST, `binding.definition` will be undefined.
#### `binding.getReferences()`
Return an array of nodes that reference this binding.
#### `binding.isReferenced()`
Check if the binding is referenced, i.e., if there are any identifier Nodes (other than `binding.definition`) referencing this binding.
#### `binding.remove(node)`
Remove a reference to this binding. Use this when you are replacing the node referencing the binding with something else.
## License
[Apache-2.0](LICENSE.md)