perf(*): about 15% faster overall in large sdk codegen by SukkaW · Pull Request #4189 · hey-api/hey-api

SukkaW · 2026-07-01T17:41:51Z

The PR follows my previous PR #3823 and #3917

Reduce ts-compiler print GC pressure by reducing object allocation: reduce spread copy, remove context object. Also, some other micro-optimizations like the faster join method.
Cache graph generation to reduce potential repeated calculations
Avoid repeated stub key population in Symbol registry
Improve pointer dependencies collection
Hoist visitor/walker for validation plugin (zod/valibot) to re-use instances
Re-use the processor instance for the TypeScript plugin
Improve walking minHeap implementation
Some early bailout for regex testing (as regex is expensive)
Micro optimization for escaping: I learned this technique back when I created fast-escape-html and fast-escape-regexp
Other micro-optimizations (replace forEach w/ plain loop, reduce closure, and more)

The PR also introduces extra phase timing tracking with debug log level, with detailed generation step time:

The Cloudflare schema generation time reduces from 10-11 seconds to 9-10 (sometimes sub-9 seconds if the download is very fast) seconds.

Also, FlameGraph comparison:

before:

after:

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vercel · 2026-07-01T17:41:56Z

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changeset-bot · 2026-07-01T17:41:57Z

🦋 Changeset detected

Latest commit: b84d40f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 4 packages

Name	Type
@hey-api/codegen-core	Patch
@hey-api/shared	Patch
@hey-api/openapi-python	Patch
@hey-api/openapi-ts	Patch

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codecov · 2026-07-01T17:46:35Z

Codecov Report

❌ Patch coverage is 86.64688% with 90 lines in your changes missing coverage. Please review.
✅ Project coverage is 40.60%. Comparing base (c1bae1d) to head (b84d40f).

Files with missing lines	Patch %	Lines
packages/openapi-ts/src/ts-compiler/printer.ts	82.89%	65 Missing and 6 partials ⚠️
packages/shared/src/openApi/shared/utils/graph.ts	89.55%	6 Missing and 1 partial ⚠️
...ges/openapi-ts/src/plugins/valibot/v1/processor.ts	0.00%	2 Missing ⚠️
...kages/openapi-ts/src/plugins/zod/mini/processor.ts	0.00%	2 Missing ⚠️
...ackages/openapi-ts/src/plugins/zod/v3/processor.ts	0.00%	2 Missing ⚠️
...ackages/openapi-ts/src/plugins/zod/v4/processor.ts	0.00%	2 Missing ⚠️
packages/shared/src/graph/walk.ts	96.66%	1 Missing and 1 partial ⚠️
packages/openapi-python/src/py-compiler/printer.ts	96.29%	1 Missing ⚠️
.../shared/src/openApi/shared/transforms/readWrite.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4189      +/-   ##
==========================================
+ Coverage   40.16%   40.60%   +0.44%     
==========================================
  Files         828      828              
  Lines       25358    25620     +262     
  Branches     7552     7628      +76     
==========================================
+ Hits        10184    10402     +218     
- Misses      12237    12277      +40     
- Partials     2937     2941       +4

Flag	Coverage Δ
unittests	`40.60% <86.64%> (+0.44%)`	⬆️

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pkg-pr-new · 2026-07-01T17:48:42Z

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@hey-api/codegen-cli

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@hey-api/codegen-core

npm i https://pkg.pr.new/@hey-api/codegen-core@4189

@hey-api/json-schema-ref-parser

npm i https://pkg.pr.new/@hey-api/json-schema-ref-parser@4189

@hey-api/nuxt

npm i https://pkg.pr.new/@hey-api/nuxt@4189

@hey-api/openapi-python

npm i https://pkg.pr.new/@hey-api/openapi-python@4189

@hey-api/openapi-ts

npm i https://pkg.pr.new/@hey-api/openapi-ts@4189

@hey-api/shared

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@hey-api/spec-types

npm i https://pkg.pr.new/@hey-api/spec-types@4189

@hey-api/types

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@hey-api/vite-plugin

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commit: b84d40f

Same technique in https://github.com/SukkaW/fast-escape-html and https://github.com/SukkaW/fast-escape-regexp

SukkaW added 11 commits July 2, 2026 01:34

perf(ts-compiler): reduce object allocation and closure

ef4153e

perf(shared): cache graph

b852377

perf(codegen-core): avoid repeated stub key space population

67bec9d

perf(shared): rewrite pointer deps collection

20927fa

feat(openapi-ts): improve generate time event debug

86e388c

perf(zod/valibot): reduce visit/walk by hoisting

8752471

perf(shared): skip sort on already emitted

ccbfccb

perf(shared): min heap, walk optimization

9cb2091

perf(openapi-ts): early bail out unicode escape

23c0155

perf(shared): micro optimization

ab7b0f5

perf(openapi-ts): typescript plugin ensure shared processor

b0b5338

SukkaW changed the title ~~perf(*): 15% faster overall sdk codegen~~ perf(*): about 15% faster overall in large sdk codegen Jul 1, 2026

perf(openapi-ts/shared): fast escaping

6e7c933

Same technique in https://github.com/SukkaW/fast-escape-html and https://github.com/SukkaW/fast-escape-regexp

SukkaW force-pushed the printter-optimization branch from c321769 to 6e7c933 Compare July 1, 2026 18:06

mrlubos added 4 commits July 2, 2026 03:19

Merge branch 'main' into printter-optimization

59aa9d5

Merge branch 'main' into printter-optimization

f63146d

docs: add changesets

7d60829

chore: fix more typecheck issues

b84d40f

mrlubos approved these changes Jul 1, 2026

View reviewed changes

mrlubos merged commit 508e443 into hey-api:main Jul 1, 2026
12 of 13 checks passed

hey-api Bot mentioned this pull request Jul 1, 2026

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perf(*): about 15% faster overall in large sdk codegen#4189

perf(*): about 15% faster overall in large sdk codegen#4189
mrlubos merged 16 commits into
hey-api:mainfrom
SukkaW:printter-optimization

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