@textlint/ast-traverse

@textlint/ast-traverse provide traversal functions for TxtAST.

This traverse function is a fork of estraverse for @textlint/markdown-to-ast.

This library is a part of textlint/textlint.

Installation

``
npm install @textlint/ast-traverse
`

Usage

`js
var parse = require("@textlint/markdown-to-ast").parse,
Syntax = require("@textlint/markdown-to-ast").Syntax;
var traverse = require("@textlint/ast-traverse").traverse,
VisitorOption = require("@textlint/ast-traverse").VisitorOption;
var AST = parse("# Header\nHelloworld");
traverse(AST, {
enter(node) {
console.log("enter", node.type);
if (node.type === Syntax.Strong) {
return VisitorOption.Skip;
}
},
leave(node) {
console.log("leave", node.type);
}
});
`

Traversal rule is the same with Estraverse.

Example

Markdown:

`markdown
Hello world
`

AST:

`json
{
"start_line": 1,
"start_column": 1,
"end_line": 0,
"children": [
{
"start_line": 1,
"start_column": 1,
"end_line": 0,
"inline_content": [
{
"c": "Hello",
"raw": "Hello",
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 5
}
},
"range": [
0,
5
],
"type": "Str"
},
{
"c": " ",
"raw": " ",
"loc": {
"start": {
"line": 1,
"column": 5
},
"end": {
"line": 1,
"column": 6
}
},
"range": [
5,
6
],
"type": "Str"
},
{
"c": [
{
"c": "world",
"raw": "world",
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 5
}
},
"range": [
0,
5
],
"type": "Str"
}
],
"raw": "world",
"loc": {
"start": {
"line": 1,
"column": 6
},
"end": {
"line": 1,
"column": 13
}
},
"range": [
6,
13
],
"type": "Emphasis"
}
],
"children": [],
"raw": "Hello world",
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 13
}
},
"range": [
0,
13
],
"type": "Paragraph"
}
],
"raw": "Hello world",
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 13
}
},
"range": [
0,
13
],
"type": "Document"
}
`

Traversal all from Root(Document node):

`
[enter, Syntax.Document],
// # Header
[enter, Syntax.Header],
[enter, Syntax.Str],
[leave, Syntax.Str],
[leave, Syntax.Header],
// => Paragraph
[enter, Syntax.Paragraph],
[enter, Syntax.Str],
[leave, Syntax.Str],
// world
[enter, Syntax.Emphasis],
[enter, Syntax.Str],
[leave, Syntax.Str],
[leave, Syntax.Emphasis],
// <= Paragraph
[leave, Syntax.Paragraph],
// End
[leave, Syntax.Document]
`

NOTE

You want to set property on Node.

Bad example:

`js
var TraverseController = require("@textlint/ast-traverse").Controller;
var controller = new TraverseController();
controller.traverse(ast, {
enter: function (node, parent) {
node.parent = parent;// it cause a circular reference!
// do something
something(node);
}
});
`

node.parent = parent; cause a circular reference!

Correct example:

`js
var TraverseController = require("@textlint/ast-traverse").Controller;
var controller = new TraverseController();
controller.traverse(ast, {
enter: function (node, parent) {
// set property as non-enumerable value
Object.defineProperty(node, "parent", {
value: parent
});
// do something
something(node);
}
});
`

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature`
5. Submit a pull request :D

License

MIT

and

Includes Estraverse

Copyright (C) 2012-2013 Yusuke Suzuki
https://github.com/estools/estraverse/blob/master/LICENSE.BSD