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https://github.com/dependents/node-source-walk
Execute a callback on every node of a source code's AST and stop walking whenever you see fit.
https://github.com/dependents/node-source-walk
ast javascript traverse
Last synced: 3 months ago
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Execute a callback on every node of a source code's AST and stop walking whenever you see fit.
- Host: GitHub
- URL: https://github.com/dependents/node-source-walk
- Owner: dependents
- License: mit
- Created: 2014-03-18T22:24:51.000Z (over 10 years ago)
- Default Branch: main
- Last Pushed: 2024-04-10T05:59:19.000Z (7 months ago)
- Last Synced: 2024-04-14T10:55:10.999Z (7 months ago)
- Topics: ast, javascript, traverse
- Language: JavaScript
- Homepage:
- Size: 396 KB
- Stars: 55
- Watchers: 4
- Forks: 6
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-ast - node-source-walk
README
# node-source-walk
[](https://github.com/dependents/node-source-walk/actions/workflows/ci.yml?query=branch%3Amain)
[](https://www.npmjs.com/package/node-source-walk)
[](https://www.npmjs.com/package/node-source-walk)
> Synchronously execute a callback on every node of a file's AST and stop walking whenever you see fit.
```sh
npm install node-source-walk
```
## Usage
```js
const Walker = require('node-source-walk');
const walker = new Walker();
// Assume src is the string contents of myfile.js
// or the AST of an outside parse of myfile.js
walker.walk(src, node => {
if (node.type === whateverImLookingFor) {
// No need to keep traversing since we found what we wanted
walker.stopWalking();
}
});
```
By default, Walker will use `@babel/parser` (supporting ES6, JSX, Flow, and all other available `@babel/parser` plugins) and the `sourceType: module`, but you can change any of the defaults as follows:
```js
const walker = new Walker({
sourceType: 'script',
// If you don't like experimental plugins
plugins: [
'jsx',
'flow'
]
});
```
* The supplied options are passed through to the parser, so you can configure it according to `@babel/parser`'s [documentation](https://babeljs.io/docs/en/babel-parser.html).
## Swap out the parser
If you want to supply your own parser, you can do:
```js
const walker = new Walker({
parser: mySweetParser
});
```
* The custom parser must have a `.parse` method that takes in a string and returns an object/AST.
* All of the other options supplied to the Walker constructor will be passed along as parser options to your chosen parser.
## API
### `walk(src, callback)`
* Recursively walks the given `src` from top to bottom
* `src`: the contents of a file **or** its (already parsed) AST
* `callback`: a function that is called for every visited node
* The argument passed to `callback` will be the currently visited node.
### `moonwalk(node, callback)`
* Recursively walks up an AST starting from the given node. This is a traversal that's in the opposite direction of `walk` and `traverse`
* `node`: a valid AST node
* `callback`: a function that is called for every node (specifically via visiting the parent(s) of every node recursively)
* The argument passed to `callback` will be the currently visited node.
### `stopWalking()`
* Halts further walking of the AST until another manual call of `walk` or `moonwalk`
* This is super-beneficial when dealing with large source files (or ASTs)
### `traverse(node, callback)`
* Allows you to traverse an AST node and execute a callback on it
* Callback should expect the first argument to be an AST node, similar to `walk`'s callback
### `parse(src)`
* Uses the options supplied to Walker to parse the given source code string and return its AST using the configured parser (or `@babel/parser` by default).
## License
[MIT](LICENSE)