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diff --git a/node_modules/estree-walker/README.md b/node_modules/estree-walker/README.md new file mode 100644 index 0000000..94dd400 --- /dev/null +++ b/node_modules/estree-walker/README.md @@ -0,0 +1,45 @@ +# estree-walker + +Simple utility for walking an [ESTree](https://github.com/estree/estree)-compliant AST, such as one generated by [acorn](https://github.com/marijnh/acorn). + + +## Installation + +```bash +npm i estree-walker +``` + + +## Usage + +```js +var walk = require( 'estree-walker' ).walk; +var acorn = require( 'acorn' ); + +ast = acorn.parse( sourceCode, options ); // https://github.com/acornjs/acorn + +walk( ast, { + enter: function ( node, parent, prop, index ) { + // some code happens + }, + leave: function ( node, parent, prop, index ) { + // some code happens + } +}); +``` + +Inside the `enter` function, calling `this.skip()` will prevent the node's children being walked, or the `leave` function (which is optional) being called. + + +## Why not use estraverse? + +The ESTree spec is evolving to accommodate ES6/7. I've had a couple of experiences where [estraverse](https://github.com/estools/estraverse) was unable to handle an AST generated by recent versions of acorn, because it hard-codes visitor keys. + +estree-walker, by contrast, simply enumerates a node's properties to find child nodes (and child lists of nodes), and is therefore resistant to spec changes. It's also much smaller. (The performance, if you're wondering, is basically identical.) + +None of which should be taken as criticism of estraverse, which has more features and has been battle-tested in many more situations, and for which I'm very grateful. + + +## License + +MIT |
