[code-infra] Setup flat build for packages by brijeshb42 · Pull Request #47670 · mui/material-ui

brijeshb42 · 2026-01-23T10:16:13Z

No more esm subdirectory inside build for es module files
Output is as per package.json's type value
For module, js files corresponds to esm and cjs files correspond to
commonjs.
For commonjs or no value, js files are commonjs and mjs files
correspond to module/esm.
Same for dts file, it'll be d.ts and d.mts for commonjs and
d.ts and d.cts for module.
Special handling had to be done for @mui/icons-material since it already has the prebuilt files. I built the files again into lib and removed old lib directory. Updated its scripts to output mjs and d.mts files as well.
All globs in package.json are now expanded to point to the files directly to have maximum bundler support (including codesandbox and stackblitz).
Exports in some of the packages have been updated to point to the exact file sine we can have only one of "./*": "./src/*/index.ts" or "./*": "./src/*/index.js"

While reviewing, please ignore the last commit has it has auto-generated files from icons package.

I have followed (at least) the PR section of the contributing guide.

mui-bot · 2026-01-23T10:19:26Z

Netlify deploy preview

https://deploy-preview-47670--material-ui.netlify.app/

Bundle size report

Bundle	Parsed size	Gzip size
@mui/material	0B^(0.00%)	0B^(0.00%)
@mui/lab	0B^(0.00%)	0B^(0.00%)
@mui/system	0B^(0.00%)	0B^(0.00%)
@mui/utils	0B^(0.00%)	0B^(0.00%)

Details of bundle changes

Generated by 🚫 dangerJS against 029f7af

brijeshb42 · 2026-02-19T14:59:44Z

.circleci/config.yml

      - run:
          name: Analyze exported typescript
          command: pnpm test:attw
+          no_output_timeout: 20m


It takes more time by attw since it now checks the paths individually. It used to skip the * paths.

brijeshb42 · 2026-02-20T10:28:44Z

packages/mui-codemod/package.json

  "author": "MUI Team",
  "description": "Codemod scripts for Material UI.",
-  "bin": "./codemod.js",
+  "bin": "./src/codemod.js",


Will get transformed after build.

brijeshb42 · 2026-02-20T10:30:54Z

packages/mui-icons-material/package.json

    "test": "pnpm --workspace-root test:unit --project \"*:@mui/icons-material\"",
    "typescript": "tsc -p tsconfig.json",
-    "attw": "attw --pack ./build --exclude-entrypoints esm --include-entrypoints Close"
+    "attw-icons": "attw --pack ./build"


Changed the script name so that it does not run with pnpm test:attw since it'll take too much time to validate with so many new entries and block the CI.
Instead, it'll now run whenever the files are built again.

brijeshb42 · 2026-02-20T10:32:55Z

packages/mui-docs/package.json

  },
  "exports": {
+    "./NProgressBar": "./src/NProgressBar/index.js",
+    "./SectionTitle": "./src/SectionTitle/index.tsx",


Explicit exports for non .ts files.

brijeshb42 · 2026-02-20T10:35:42Z

packages/mui-material/package.json

+    "./transitions": "./src/transitions/index.ts",
+    "./useLazyRipple": "./src/useLazyRipple/index.ts",
+    "./version": "./src/version/index.ts",
+    "./*": "./src/*/index.js"


Explicit listing of .ts entrypoints since they are less in number than .js entrypoints.

docs/data/material/getting-started/templates/checkout/components/PaymentForm.tsx

1. No more `esm` subdirectory inside `build` for es module files 2. Output is as per package.json's type value 3. For module, js files corresponds to esm and cjs files correspond to commonjs. 4. For commonjs or no value, js files are commonjs and mjs files correspond to module/esm. 5. Same for dts file, it'll be `d.ts` and `d.mts` for commonjs and `d.ts` and `d.cts` for module.

siriwatknp · 2026-02-23T03:39:12Z

Looks good https://stackblitz.com/run?file=src%2FDemo.tsx

siriwatknp

👍 Two questions

Would this PR improve speed for bundling @mui/icons-material from the user-land in any way?
Is this consider a breaking change? or at least would it impact any project setup?

brijeshb42 · 2026-02-23T03:58:23Z

Would this PR improve speed for bundling @mui/icons-material from the user-land in any way?

Not really if they are using barrel imports.

Is this consider a breaking change? or at least would it impact any project setup?

Its not a breaking change. I want to test this in alpha though just in case. If everything works, we can look into back-porting it.
If someone has setup some kind of aliasing in their bundler setup to point to the esm folder directly, then they are using undocumented private paths which will break for them.

brijeshb42 requested a review from a team January 23, 2026 10:16

brijeshb42 added the scope: code-infra Involves the code-infra product (https://www.notion.so/mui-org/5562c14178aa42af97bc1fa5114000cd). label Jan 23, 2026

brijeshb42 mentioned this pull request Jan 23, 2026

[code-infra] Support flat build output behind a flag mui/mui-public#1064

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brijeshb42 force-pushed the flat-build branch from f935950 to 699f017 Compare January 23, 2026 10:16

brijeshb42 force-pushed the flat-build branch 2 times, most recently from 538021a to ffaafcb Compare January 23, 2026 17:31

github-actions bot added the PR: out-of-date The pull request has merge conflicts and can't be merged. label Jan 24, 2026

brijeshb42 force-pushed the flat-build branch from ffaafcb to 47bde0e Compare January 26, 2026 05:17

github-actions bot removed the PR: out-of-date The pull request has merge conflicts and can't be merged. label Jan 26, 2026

brijeshb42 force-pushed the flat-build branch 3 times, most recently from 0726c3b to 215cbb3 Compare January 27, 2026 10:32

github-actions bot added the PR: out-of-date The pull request has merge conflicts and can't be merged. label Jan 28, 2026

brijeshb42 force-pushed the flat-build branch from 215cbb3 to 3bfe54e Compare February 10, 2026 11:06

github-actions bot added PR: out-of-date The pull request has merge conflicts and can't be merged. and removed PR: out-of-date The pull request has merge conflicts and can't be merged. labels Feb 10, 2026

brijeshb42 force-pushed the flat-build branch from da5075d to c9af863 Compare February 10, 2026 15:59

github-actions bot removed the PR: out-of-date The pull request has merge conflicts and can't be merged. label Feb 10, 2026

brijeshb42 force-pushed the flat-build branch 4 times, most recently from 9da8f34 to 83de605 Compare February 11, 2026 16:59

github-actions bot added the PR: out-of-date The pull request has merge conflicts and can't be merged. label Feb 11, 2026

brijeshb42 force-pushed the flat-build branch from 83de605 to 1e7a971 Compare February 11, 2026 17:48

github-actions bot added PR: out-of-date The pull request has merge conflicts and can't be merged. and removed PR: out-of-date The pull request has merge conflicts and can't be merged. labels Feb 11, 2026

brijeshb42 force-pushed the flat-build branch from 1e7a971 to 40ba657 Compare February 19, 2026 05:51

github-actions bot removed the PR: out-of-date The pull request has merge conflicts and can't be merged. label Feb 19, 2026

brijeshb42 force-pushed the flat-build branch from 2437862 to bfb3ceb Compare February 19, 2026 13:06

brijeshb42 requested a review from a team February 19, 2026 13:33

github-actions bot added the PR: out-of-date The pull request has merge conflicts and can't be merged. label Feb 19, 2026

brijeshb42 force-pushed the flat-build branch from bfb3ceb to 71dd2b5 Compare February 19, 2026 14:57

github-actions bot removed the PR: out-of-date The pull request has merge conflicts and can't be merged. label Feb 19, 2026

brijeshb42 force-pushed the flat-build branch from 71dd2b5 to ff44f99 Compare February 19, 2026 14:58

brijeshb42 commented Feb 19, 2026

View reviewed changes

github-actions bot added the PR: out-of-date The pull request has merge conflicts and can't be merged. label Feb 19, 2026

brijeshb42 force-pushed the flat-build branch from ff44f99 to 90da40c Compare February 19, 2026 16:08

github-actions bot removed the PR: out-of-date The pull request has merge conflicts and can't be merged. label Feb 19, 2026

brijeshb42 commented Feb 20, 2026

View reviewed changes

brijeshb42 force-pushed the flat-build branch from 90da40c to c67d073 Compare February 20, 2026 10:37

siriwatknp reviewed Feb 20, 2026

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docs/data/material/getting-started/templates/checkout/components/PaymentForm.tsx Outdated Show resolved Hide resolved

brijeshb42 force-pushed the flat-build branch 2 times, most recently from 43ff752 to 74f1553 Compare February 20, 2026 12:03

brijeshb42 requested a review from siriwatknp February 20, 2026 12:41

brijeshb42 added 2 commits February 20, 2026 20:29

discard: auto generated lib icon files

029f7af

brijeshb42 force-pushed the flat-build branch from 74f1553 to 029f7af Compare February 20, 2026 15:00

siriwatknp approved these changes Feb 23, 2026

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brijeshb42 merged commit 89071b1 into mui:master Feb 23, 2026
23 checks passed

brijeshb42 deleted the flat-build branch February 23, 2026 03:59

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[code-infra] Setup flat build for packages#47670

[code-infra] Setup flat build for packages#47670
brijeshb42 merged 2 commits intomui:masterfrom
brijeshb42:flat-build

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