[BUG]: Types are randomly renamed

[ccarstens]

Quicktype CLI renames types randomly, making it really unreliable. E.g. The json schema below results in a typescript interface named Light instead of LightParams

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$defs": {
    "LightParams": {
      "properties": {
        "outlet_id": {
          "type": "string"
        },
        "app_id": {
          "type": "string"
        },
        "rgba": {
          "type": "string"
        }
      },
      "additionalProperties": false,
      "type": "object",
      "required": [
        "outlet_id",
        "app_id",
        "rgba"
      ]
    }
  },
  "properties": {
    "LightParams": {
      "$ref": "#/$defs/LightParams"
    }
  },
  "additionalProperties": false,
  "type": "object",
  "required": [
    "LightParams"
  ]
}

Issue Type

The issue is the unpredictable renaming of types at runtime.

Context (Environment, Version, Language)

CLI v23.1.4

Input Format: JSON Schema
Output Language: Typescript

I'm using the CLI

CLI, npm, or app.quicktype.io:
Version: v23.1.4

Description

I'm trying to generate types that have predictable names. I want to have control over the name of a type by just naming it that way.

Input Data

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$defs": {
    "LightParams": {
      "properties": {
        "outlet_id": {
          "type": "string"
        },
        "app_id": {
          "type": "string"
        },
        "rgba": {
          "type": "string"
        }
      },
      "additionalProperties": false,
      "type": "object",
      "required": [
        "outlet_id",
        "app_id",
        "rgba"
      ]
    }
  },
  "properties": {
    "LightParams": {
      "$ref": "#/$defs/LightParams"
    }
  },
  "additionalProperties": false,
  "type": "object",
  "required": [
    "LightParams"
  ]
}

Expected Behaviour / Output

I want to receive an interface named LightParams not Light since I named it that way and I never said to cut off random parts of my type name.

Current Behaviour / Output

Quicktype removes the "Params" suffix. The same happens with other words like Value or Parameter.

Steps to Reproduce

quicktype --src-lang schema --lang ts -o $output_file --just-types --no-date-times --alphabetize-properties $input_file

Possible Solution

Add an option to deactivate the arbitrary renaming of types.

[acidnik]

Got same problem, here's relevant log lines with --debug all

class QuestStage was renamed to Stage

45: object stage | children 29,46,8,36,39,49,51,3 | 411,412,413,417,418,531,532,535,536,537,538 | distance 1 Stage,QuestStage,SlotQuestStage () | Quest..., ...
45: object stage | children 29,46,8,36,39,49,51,3 | 411,412,413,417,418,531,532,535,536,537,538 | distance 1 Stage,QuestStage,SlotQuestStage (stage_element,stage_object,scene_object_stage,scene_object_stage_object) | Quest..., ...

[schani]

Triage sweep note (systematic backlog triage, assisted by Claude): confirmed reproducible on current master (v23.3.0, commit 68ecb28).

Root cause: definitionName in packages/quicktype-core/src/input/JSONSchemaInput.ts (~lines 305-311) only recognizes the legacy "definitions" keyword, not "$defs" (the standard name since draft 2019-09). As a result the name given under $defs is never treated as a "given name" for the type. The type keeps only its inferred names (LightParams from the property, plus a file-derived light.schema), and combineNames in packages/quicktype-core/src/attributes/TypeNames.ts merges those by common prefix (light_), producing Light. Renaming $defs to definitions in the same schema correctly yields LightParams, confirming the cause.

Assessment:

• Severity: low — names come out wrong but the generated code still compiles and is usable.
• Fix difficulty: easy — accept "$defs" alongside "definitions" in definitionName (JSONSchemaInput.ts line ~308) and update the affected test snapshots.

Reproduction:

node dist/index.js --src-lang schema --lang ts --just-types --no-date-times --alphabetize-properties light.schema.json

light.schema.json:

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$defs": {
    "LightParams": {
      "properties": {
        "outlet_id": { "type": "string" },
        "app_id": { "type": "string" },
        "rgba": { "type": "string" }
      },
      "additionalProperties": false,
      "type": "object",
      "required": ["outlet_id", "app_id", "rgba"]
    }
  },
  "properties": {
    "LightParams": { "$ref": "#/$defs/LightParams" }
  },
  "additionalProperties": false,
  "type": "object",
  "required": ["LightParams"]
}

Output names the interface Light instead of LightParams.