@pyts/tsparser

TypeScript AST parser and code generator from JSON.

This library receives a JSON representation of TypeScript AST nodes (generated by pytsast) and converts them to actual TypeScript code.

Installation

npm install @pyts/tsparser

Usage

From JSON String

import { parseAndPrint } from '@pyts/tsparser';

const json = JSON.stringify({
  type: 'factory',
  name: 'createIdentifier',
  args: [{ type: 'literal', value: 'myVariable' }],
});

const code = parseAndPrint(json);
console.log(code); // myVariable

From Serialized Object

import { toTypeScript } from '@pyts/tsparser';

const serialized = {
  type: 'factory',
  name: 'createImportDeclaration',
  args: [
    // ... serialized args from pytsast
  ],
};

const code = toTypeScript(serialized);
console.log(code);

Low-Level API

import { deserialize, printNode } from '@pyts/tsparser';
import ts from 'typescript';

// Deserialize JSON to TypeScript AST
const node = deserialize(serializedJson) as ts.Node;

// Print the node as TypeScript code
const code = printNode(node, { trailingNewline: true });

API

High-Level Functions

• parse(json: string): ts.Node - Parse JSON string to AST node
• parseAndPrint(json: string, options?): string - Parse and print as code
• toTypeScript(node: SerializedNode, options?): string - Convert object to code
• toTypeScriptFile(nodes: SerializedNode[], options?): string - Multiple nodes to file

Deserializer Functions

• deserialize(node: SerializedNode): DeserializedValues - Deserialize any node
• deserializeStatement(node): ts.Statement - Deserialize as statement
• deserializeStatements(nodes): ts.Statement[] - Deserialize statement array
• deserializeExpression(node): ts.Expression - Deserialize as expression
• deserializeDeclaration(node): ts.DeclarationStatement - Deserialize as declaration

Printer Functions

• printNode(node: ts.Node, options?): string - Print single node
• printNodes(nodes: ts.Node[], options?): string - Print multiple nodes
• printFile(statements: ts.Statement[], options?): string - Print as file

Type Guards

• isLiteral(node): node is SerializedLiteral
• isNumber(node): node is SerializedNumber
• isFactory(node): node is SerializedFactory

Serialization Format

The JSON format matches the output from pytsast:

{
  "type": "factory",
  "name": "createIdentifier",
  "args": [
    { "type": "literal", "value": "myVar" }
  ]
}

Node Types

• literal: { type: "literal", value: null | boolean | string }
• undefined: { type: "undefined"}
• number: { type: "number", value: number | string }
• factory: { type: "factory", name: string, args: SerializedNode[] }

Integration with pytsast

# Python side
>>> from pytsast import factory as ts
>>> import json
>>> 
>>> node = ts.createIdentifier("hello")
>>> json_output = json.dumps(node.serialize().model_dump(), indent=2)
>>> print(json_output)
{
  "type": "factory",
  "name": "createIdentifier",
  "args": [
    {
      "type": "literal",
      "value": "hello"
    }
  ]
}

// TypeScript side
> import { parseAndPrint } from '@pyts/tsparser';
> 
> const jsonFromPython = '...'; // Output from Python
> const tsCode = parseAndPrint(jsonFromPython);
> console.log(tsCode);
hello