Typescript Interface Parser (and to JSON converter)

The typescript interface parser parses interfaces defined in typescript and outputs a JSON object describing the interfaces.

Features

• output to file and to stdio
• comments are also considered and provided by the JSON representation
• supports a wide range of typescript syntax (if you find something missing please file a feature request)
• can be easily integrated in your own program for parsing typescript interfaces

Table of Contents

1. Installation
   1. Pypi
   2. Manual Installation
   3. Running the Unit Tests
2. The JSON Representation
   1. Translation of Attributes
   2. Indexed Attributes
   3. Function Attributes

MISC

I needed to communicate with a server via RPC from a Python client, but all valid messages were specified in Typescript interfaces. There were a huge number of different messages and I slowly got bored translating the interfaces manually. So I implemented this translator. Hope it will serve you, as well as it served me.

Installation

Pypi

pip install ts-interface-parser

Manual installation

Clone the repo and install the requirements with pip install -r requirements.txt. Than type python3 ts_interface_parser.py -h to get an overview of the possible options.

Running the Unit Tests

python3 -m unittest test.test_parser.TestParser

The JSON Representation

The general translation works as follows:

/**
* <some comment>
*/
interface <interface_name> extends <extension_a>, <extension_b> {
        <attribute_1> : <type_1>;
}

is translated to

{
        "<interface_name>" : {
                "description" : "<some comment>",
                "extends": [
                        "<extension_a>",
                        "<extension_b>"
                ]
                "<attribute_1> : {
                        "type" : [
                                "<type_1>"
                        ]
                }
        }
}

The comment becomes the decsription and potential extensions are provided in the extends field. For every specified attribute an object is added referenced by the name of the attribute. Here <attribute_1>.

Translation of Attributes

In the following I give examples of different attribute definitions and how those are translated into JSON.

interface <interface_name> {
        <attribute_name_1> : <type_1> | <type_2>; // <comment_1>
        /**
        * <comment_2>
        */
        <attribute_name_2> : {
                <attribute_name_3> : <type_3>
        }

        <attribute_name_4>? : <type_4>;

        const <attribute_name_5> : <type_5>;

        readonly <attribute_name_6> : <type_6>;

        <attribute_name_7> : "value 1" | "value 2";
}

is translated to

{
        "<interface_name>" : {
                "<attribute_name_1>" : {
                        "description" : "<comment_1">,
                        "type" : [
                                "type_1",
                                "type_2"
                        ]
                },
                "<attribute_name_2>" : {
                        "description" : "<comment_2">,
                        "type": {
                                "<attribute_name_3>" : {
                                        "type" : [
                                                "type_3"
                                        ]
                                }
                        }
                },
                "<attribute_name_4>" : {
                        "optional" : true,
                        "type" : [
                                "<type_4>"
                        ]
                },
                "<attribute_name_5>" : {
                        "constant" : true,
                        "type" : [
                                "<type_5>"
                        ]
                },
                "<attribute_name_6>" : {
                        "readonly" : true,
                        "type" : [
                                "<type_6>"
                        ]
                },
                "<attribute_name_7>" : {
                        "type" : [
                                "'value 1'",
                                "'value 2'",
                        ]
                }
        }
}

Indexed Attributes

interface ReadonlyStringArray {
        [index: number]: string;
}

The indexed attribute is named with the variable name within the square brackets. The attribute has a field indexed which contains the index type and the type the index is refering to.

{
        "ReadonlyStringArray": {
                "index": {
                        "indexed": {
                                "type": [
                                        "number"
                                ]
                        },
                        "type": [
                                "string"
                        ]
                }
        }
}

Function Attributes

Functions are marked by a field function in the JSON representation of the function. Thus

interface ClockInterface {
        setTime(d: Date): void;
}

translates to

{
        "ClockInterface": {
                "setTime": {
                        "function": true,
                        "parameters": {
                                "d": {
                                        "type": [
                                                "Date"
                                        ]
                                }
                        },
                        "type": [
                                "void"
                        ]
                }
}

For anonymous function declarations, as for instance:

interface SearchFunc{
        (source: string, subString: string): boolean;
}

This interface is translated to:

{
        "SearchFunc": {
                "anonymous_function": {
                    "function": true,
                    "parameters": {
                        "source": {
                            "type": [
                                "string"
                            ]
                        },
                        "subString": {
                            "type": [
                                "string"
                            ]
                        }
                    },
                    "type": [
                        "boolean"
                    ]
                }
        }
}