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inline combined types by default, add useCombinedTypeAliases opt-out #2654

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melloware merged 5 commits into from
Dec 17, 2025
Merged

inline combined types by default, add useCombinedTypeAliases opt-out #2654

melloware merged 5 commits into from
Dec 17, 2025

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@superxiao
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@superxiao superxiao commented Dec 16, 2025 •
edited
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Breaking change: Inlines combined types by default, cleaning up generated types by removing unnecessary intermediate type aliases.

Helps with #1644 - eliminates verbose names like ListOfActivitiesResponseAnyOfDataAnyOfItem....

// orval.config.ts - to restore old behavior
output: {
  override: {
    useCombinedTypeAliases: true,
  },
},

Estimated impact on a real project:

Metric Before After Change
Types 1,549 ~252 -84%
Lines 7,156 ~5,859 -18%

Fewer intermediate types means better readability and potentially faster type inference.

The change handles two cases:

1. Intermediate object types - things like ResponseAnyOf, ResponseOneOfTwo go away:

// before
export type Response401OneOf = { defined: true; ... };
export type Response401OneOfTwo = { defined: false; ... };
export type Response401 = Response401OneOf | Response401OneOfTwo;

// after
export type Response401 = { defined: true; ... } | { defined: false; ... };

2. Primitive union properties - explicit anyOf/oneOf with primitives get inlined:

// before (anyOf: [{type: string}, {type: number}])
export type MyObjectField = string | number;
export interface MyObject {
  field?: MyObjectField;
}

// after
export interface MyObject {
  field?: string | number;
}

Set useCombinedTypeAliases: true to restore the old behavior of creating intermediate type aliases.

Property-level inline objects still get named types (complex types benefit from a name anyway):

// anyOf with inline objects at property level - still creates named type
export type MyObjectResult = { data?: string } | { error?: string };
export interface MyObject {
  result?: MyObjectResult;
}

@superxiao
feat(core): add inlineCombinedTypes option to inline union/intersecti…
e0087bb 
…on types

When enabled, combined types (anyOf/oneOf/allOf) are inlined instead of
creating intermediate type aliases like ResponseAnyOf, MyObjectField.

- Add inlineCombinedTypes option (default: false for backward compatibility)
- Skip intermediate propName generation in combineSchemas when enabled
- Use conditional regex in resolveObject to only match '{' when enabled
@superxiao
test(core): add test for property-level inline objects keeping named …
b458cb7 
…types
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superxiao commented Dec 16, 2025

As the real world example in the PR description shows, such an option could cut down some excessive single-use types for a project I'm working on (where the generated file is still growing fast). Let me know if you think this is a good idea or not.

@melloware
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melloware commented Dec 16, 2025

@anymaniax @soartec-lab what do you think? I am all for less generated code...

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soartec-lab commented Dec 17, 2025

@superxiao @melloware
I agree with this. I don't find many cases where I want to refer to polymorphic types, so it might be a good idea to make this behavior the default and separate types optional. If that's the case, V8 is the right time.

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melloware commented Dec 17, 2025

agreed this should be the default.

@melloware melloware added the enhancement New feature or request label Dec 17, 2025
@melloware melloware added this to the 8.0.0 milestone Dec 17, 2025
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melloware commented Dec 17, 2025

@superxiao can you make this the default true and make them opt out of it with false

@superxiao
refactor(core): rename inlineCombinedTypes to useCombinedTypeAliases
7599dc8 
- Rename flag from inlineCombinedTypes to useCombinedTypeAliases
- Default to false (inline by default, opt-in to create aliases)
- Simplify logic: if (useCombinedTypeAliases) instead of === false check
- Update tests to verify default behavior with unmodified context
@superxiao superxiao changed the title add inlineCombinedTypes option to reduce intermediate type aliases inline combined types by default, add useCombinedTypeAliases opt-out Dec 17, 2025
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superxiao commented Dec 17, 2025 •
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PR has been updated to make the inlining default behavior. New option is renamed from inlineCombinedTypes to useCombinedTypeAliases - false and undefined is the default.

@melloware melloware linked an issue Dec 17, 2025 that may be closed by this pull request
Orval overuses AnyOf types delimiter #1644
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melloware commented Dec 17, 2025

This is fantastic!

@melloware melloware merged commit 9f649d6 into orval-labs:master Dec 17, 2025
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soartec-lab commented Dec 18, 2025

@superxiao
Thanks for great improvement. Could you also make a PR to document it?

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superxiao commented Dec 19, 2025

#2657

@ScriptType ScriptType mentioned this pull request Dec 30, 2025
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Orval overuses AnyOf types delimiter

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