Avro Typescript

A simple JS library to convert Avro Schemas to TypeScript interfaces.

Install

npm install avro-typescript

The library can be run in node.js or the browser. It takes a Avro Schema as a JavaScript object (from JSON) and returns the TypeScript code as a string.

Usage

import { avroToTypeScript, RecordType } from "avro-typescript"

const schemaText = fs.readFileSync("example.avsc", "UTF8");
const schema = JSON.parse(schemaText) as RecordType;
console.log(avroToTypeScript(schema as RecordType));

Override logicalTypes

Tools like avsc allow you to override the serialization/deserialization of LogicalTypes, say from numbers to native JS Date objects, in this case we want to generate the typescript type as 'Date', not 'number'. Therefore, you can pass in a map 'logicalTypes' to the options to override the outputted TS type for the schema logicalType.

For example:

const schema: Schema = {
    type: "record",
    name: "logicalOverrides",
    fields: [
        {
            name: "eventDate",
            type: {
                type: "int",
                logicalType: "date",
            },
        },
        {
            name: "startTime",
            type: {
                type: "int",
                logicalType: "timestamp-millis",
            },
        },
        {
            name: "displayTime",
            type: {
                type: "string",
                logicalType: "iso-datetime",
            },
        },
    ],
};
const actual = avroToTypeScript(schema, {
logicalTypes: {
    date: 'Date',
    'timestamp-millis': 'Date',
}
});

// this will output
export interface logicalOverrides {
    eventDate: Date;
    startTime: Date;
    displayTime: string;
}

Features

Most Avro features are supported, including:

• Enumerated Types
• Maps
• Named Records
• Mandatory and optional fields
• Unions
• Primitives

To-do

• Generate a function to set defaults as per the schema
• Add support for fixed
• Generate JSDocs from documentation
• Add namespace support