https://github.com/JohannesOehm/json-parse-ast

JSON AST parser written in JavaScript. For usage in conjunction with the monaco editor to enhance JSON autocomplete experience.
https://github.com/JohannesOehm/json-parse-ast

Last synced: about 1 month ago
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JSON AST parser written in JavaScript. For usage in conjunction with the monaco editor to enhance JSON autocomplete experience.

• Host: GitHub
• URL: https://github.com/JohannesOehm/json-parse-ast
• Owner: JohannesOehm
• Created: 2021-02-21T12:39:37.000Z (almost 4 years ago)
• Default Branch: master
• Last Pushed: 2021-02-25T13:12:36.000Z (almost 4 years ago)
• Last Synced: 2024-09-20T13:18:10.516Z (3 months ago)
• Language: JavaScript
• Size: 118 KB
• Stars: 4
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: Readme.md

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README

        
# json-parse-ast

JSON Tokenizer & AST (Abstract Syntax Tree) parser

## Background

I wrote my custom parser since [monaco's](https://microsoft.github.io/monaco-editor/) built-in JSON

library does not expose any syntax tree which can be used to check position in file and enhance 

autocomplete experience.

## Usage

Currently, only tokenizer is stable:

```javascript

var tokens = tokenize('{"json": "string"}'); //returns list of tokens

//tokens have the following attributes

// type: "inlinecomment"|"multilinecomment"|"whitespace"|"string"|"literal"|"number"|"punctuaction" 

// position: IRange compatible with monaco's IRange-interface

// raw: string 

// value: string Unescaped JSON string, parsed number, parsed literal (null, true, false)

```

## Tokenizer additional features

```javascript

var [path, willBeValue] = getPathInObject(tokenize('{"foo": {"bar": "'));

//returns path == ["foo", "bar"] and willBeValue == true

```

## Parser

```javascript

var ast = parseTokens(tokenize(testString));

//AST elements have

// type 

// position: IRange

// raw: string

// value?: string

// parent?: AST 

// children?: AST[]

//Find node at specified position

var node = findAtPosition(ast, {lineNumber: 4, column: 16})

```

## Usage with monaco

This libraries intended use is for enhancing experience with custom JSON formats. See example use-cases below:

### Enhancing autocomplete/IntelliSense

```javascript

monaco.languages.registerCompletionItemProvider('json', {

    provideCompletionItems: function(model, position) {

        let textUntilPosition = model.getValueInRange({startLineNumber: 1, startColumn: 1, endLineNumber: position.lineNumber, endColumn: position.column});

        let [jsonPath, willBeValue] = getPathInObject(tokenize(textUntilPosition));

        if (willBeValue && jsonPath[jsonPath.length-1] === "dependencies") {

             return { suggestions: listDependencies() };

        } else {

             return { suggestions: [] };

        }

    }

});

```