https://github.com/estools/esdispatch

trigger events based on esquery selectors during a traversal of a SpiderMonkey format AST
https://github.com/estools/esdispatch

ast ecmascript estree javascript

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trigger events based on esquery selectors during a traversal of a SpiderMonkey format AST

• Host: GitHub
• URL: https://github.com/estools/esdispatch
• Owner: estools
• License: bsd-3-clause
• Created: 2013-09-29T13:55:33.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2014-09-09T16:39:14.000Z (over 10 years ago)
• Last Synced: 2024-10-05T16:19:37.377Z (4 months ago)
• Topics: ast, ecmascript, estree, javascript
• Language: CoffeeScript
• Homepage:
• Size: 146 KB
• Stars: 12
• Watchers: 5
• Forks: 4
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# esdispatch

Trigger events based on [esquery](https://github.com/jrfeenst/esquery) selectors during a traversal of a [SpiderMonkey format AST](https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API).

## Install

    npm install --save esdispatch

## Examples

```js

var counter = 0, dispatcher = new ESDispatcher;

dispatcher.on(

  'UpdateExpression[operator="++"] > Identifier[name=i]',

  function(node, ancestors) { ++counter; }

);

dispatcher.observe(spidermonkeyAST, function() {

  counter; // 4

});

```

## API

#### `new ESDispatcher` → ESDispatcher instance

The ESDispatcher constructor takes no arguments.

#### `ESDispatcher::addListener(selector, listener)` → void

Invoke `listener` whenever esdispatch walks over a node that matches

`selector`. `listener` is given two arguments: the node that matched the

selector, and a list containing the ancestors of that node. `listener` may also

be an object containing an `enter` and, optionally, a `leave` function. In that

case, the `enter` function will be called in pre-order, and the `leave`

function will be called in post-order. Aliased as `ESDispatcher::on`.

#### `ESDispatcher::once(selector, listener)` → void

Adds a listener that is invoked only the first time `selector` matches.

#### `ESDispatcher::observe(ast, onFinished)` → void

Begin a traversal using the given SpiderMonkey AST, triggering any listeners

associated with matching queries. `onFinished`, if given, is called with no

arguments once the traversal is completed.