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https://github.com/tree-sitter/node-tree-sitter

Node.js bindings for tree-sitter
https://github.com/tree-sitter/node-tree-sitter

binding javascript nodejs tree-sitter

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Node.js bindings for tree-sitter

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README

        

node tree-sitter
================

Incremental parsers for node

### Installation

```sh
npm install tree-sitter
```

### Usage

First, you'll need a Tree-sitter grammar for the language you want to parse. There are many [existing grammars](https://github.com/tree-sitter) such as [tree-sitter-javascript](http://github.com/tree-sitter/tree-sitter-javascript) and [tree-sitter-go](http://github.com/tree-sitter/tree-sitter-go). You can also develop a new grammar using the [Tree-sitter CLI](https://github.com/tree-sitter/tree-sitter/tree/master/cli).

Once you've got your grammar, create a parser with that grammar.

```javascript
const Parser = require('tree-sitter');
const JavaScript = require('tree-sitter-javascript');

const parser = new Parser();
parser.setLanguage(JavaScript);
```

Then you can parse some source code,

```javascript
const sourceCode = 'let x = 1; console.log(x);';
const tree = parser.parse(sourceCode);
```

and inspect the syntax tree.

```javascript
console.log(tree.rootNode.toString());

// (program
// (lexical_declaration
// (variable_declarator (identifier) (number)))
// (expression_statement
// (call_expression
// (member_expression (identifier) (property_identifier))
// (arguments (identifier)))))

const callExpression = tree.rootNode.child(1).firstChild;
console.log(callExpression);

// { type: 'call_expression',
// startPosition: {row: 0, column: 16},
// endPosition: {row: 0, column: 30},
// startIndex: 0,
// endIndex: 30 }
```

If your source code *changes*, you can update the syntax tree. This will take less time than the first parse.

```javascript
// Replace 'let' with 'const'
const newSourceCode = 'const x = 1; console.log(x);';

tree.edit({
startIndex: 0,
oldEndIndex: 3,
newEndIndex: 5,
startPosition: {row: 0, column: 0},
oldEndPosition: {row: 0, column: 3},
newEndPosition: {row: 0, column: 5},
});

const newTree = parser.parse(newSourceCode, tree);
```

### Parsing Text From a Custom Data Structure

If your text is stored in a data structure other than a single string, you can parse it by supplying a callback to `parse` instead of a string:

```javascript
const sourceLines = [
'let x = 1;',
'console.log(x);'
];

const tree = parser.parse((index, position) => {
let line = sourceLines[position.row];
if (line) {
return line.slice(position.column);
}
});
```