bcherny/json-schema-to-typescript

properties + anyOf generates incorrect output

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#567 opened on Jan 11, 2024

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Description

Given this schema:

{
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "id": {
      "type": "string"
    },
    "validFrom": {
      "type": "string"
    },
    "validTo": {
      "type": "string"
    }
  },
  "anyOf": [
    {
      "required": ["id", "validFrom"]
    },
    {
      "required": ["id", "validTo"]
    }
  ],
  "title": "Assortment"
}

This is the type generated:

export type Assortment = Assortment1 & Assortment2;
export type Assortment1 = {
  [k: string]: unknown;
};

export interface Assortment2 {
  id?: string;
  validFrom?: string;
  validTo?: string;
}

And I was hoping it would generate something like this:

export type Assortment =
  | {
      id: string;
      validFrom: string;
      validTo?: string;
    }
  | {
      id: string;
      validFrom?: string;
      validTo: string;
    };

I might be doing something wrong, so my apologies in advance.

Thank you so much!

Contributor guide

Research direction
Investigate the code path that handles `anyOf` combined with `properties`. Look at how the schema with `anyOf` and `properties` is processed and why it results in an intersection type instead of a union. Check if there is logic that merges `properties` into a shared base and then applies `anyOf` separately, leading to incorrect type generation.
Tech stack
typescript
Domain
tooling
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JSON SchemaTypeScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75