bcherny/json-schema-to-typescript

Add support for `unevaluatedProperties` keyword

Open

#442 opened on Feb 28, 2022

View on GitHub
 (3 comments) (19 reactions) (0 assignees)TypeScript (449 forks)github user discovery
enhancementgood first issuehelp wanted

Repository metrics

Stars
 (3,302 stars)
PR merge metrics
 (No merged PRs in 30d)

Description

Draft 2019-09 introduces the new keyword unevaluatedProperties, which seems not supported in this project yet.

A schema with "unevaluatedProperties": false will lead to the generated type definition containing an extra [k: string]: unknown; field, which is expected not to be seen.

Reproduction

Schema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "title": "Foo",
  "properties": {
    "bar": {
      "type": "string"
    }
  },
  "unevaluatedProperties": false
}

yields

export interface Foo {
  bar?: string;
  [k: string]: unknown;
}

which is expected to be

export interface Foo {
  bar?: string;
}

instead.

Contributor guide

Research direction
Investigate how the compiler currently handles the `additionalProperties` keyword and `unevaluatedProperties` from Draft 2019-09. Modify the schema normalization to treat `unevaluatedProperties: false` similarly to `additionalProperties: false` but only for properties not evaluated by any applicator (including `if/then/else`, `allOf`, etc.). Ensure that the generated type does not include `[k: string]: unknown` when `unevaluatedProperties` is set to false.
Tech stack
typescript
Domain
developer experience
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
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
TypeScriptJSON Schema
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70