Developer
Marco Wang
marcoww@meta.com
Performance
Key patterns and highlights from this developer's activity.
Breakdown of growth, maintenance, and fixes effort over time.
Bugs introduced vs. fixed over time.
No bugs introduced or fixed in this period.
Reclassifies engineering effort based on bug attribution. Commits that introduced bugs are retrospectively counted as poor investments.
Investment Quality reclassifies engineering effort based on bug attribution data. Commits identified as buggy origins (those that introduced bugs later fixed by someone) have their grow and maintenance time moved into the Wasted Time category. Their waste (fix commits) remains counted as productive. All other commits retain their standard classification: grow is productive, maintenance is maintenance, and waste (fixes) is productive.
The standard model classifies commits as Growth, Maintenance, or Fixes. Investment Quality adds a quality lens: a commit that introduced a bug is retrospectively counted as a poor investment — the engineering time spent on it was wasted because it ultimately required additional fix work. Fix commits (Fixes in the standard model) are reframed as productive, because fixing bugs is valuable work.
Currently computed client-side from commit and bug attribution data. Ideal server-side endpoint:
POST /v1/organizations/{orgId}/investment-quality
Content-Type: application/json
Request:
{
"startTime": "2025-01-01T00:00:00Z",
"endTime": "2025-12-31T23:59:59Z",
"bucketSize": "BUCKET_SIZE_MONTH",
"groupBy": ["repository_id" | "deliverer_email"]
}
Response:
{
"productivePct": 74,
"maintenancePct": 18,
"wastedPct": 8,
"buckets": [
{
"bucketStart": "2025-01-01T00:00:00Z",
"productive": 4.2,
"maintenance": 1.8,
"wasted": 0.6
}
]
}Latest analyzed commits from this developer.
| Hash | Message | Date | Files |
|---|
Commit activity distribution by hour and day of week. Shows when this developer is most active.
Developers who frequently work on the same files and symbols. Higher score means stronger code collaboration.
| Effort |
|---|
| 6c035760 | This commit performs a **maintenance update** by upgrading the **Flow type checker version** used in the project from `0.306.1` to `0.307.0`. Specifically, the `.flowconfig` file is modified to reflect this new version, ensuring the project's **type checking system** is aligned with the latest Flow release. This change impacts the entire codebase by potentially introducing new type errors or resolving existing ones, thereby affecting the **development toolchain** and overall code quality enforcement. | Mar 28 | 3 | maint |
| 4f0bd0ee | This commit performs a **codemod** to update the **Flow type parameter bound syntax** within the **`react-native-codegen` package**. It **refactors** type definitions in `CodegenSchema.js` and parser utilities in `parsers-commons.js`, migrating from the deprecated colon-style bounds to the modern `extends` keyword. Specifically, `Nullable`, `NativeModuleArrayTypeAnnotation`, `unwrapNullable`, and `wrapNullable` are updated to align with current Flow syntax. This **maintenance** task ensures compatibility with newer Flow versions and improves the consistency of type annotations within the codegen tooling, without altering the runtime behavior or generated code. | Mar 11 | 2 | maint |
| b8876b56 | This commit **updates the `react-native-codegen` package** to switch its JavaScript parsing engine from Babel to **Hermes**. This **tooling change** involves modifying the `package.json` to reflect the new dependency and adding the `babel-plugin-syntax-hermes-parser` to the `.babelrc` configuration. The primary impact is on the internal **code generation process**, ensuring it leverages Hermes for potentially improved parsing performance and compatibility. This is a **maintenance update** for the development tools. | Mar 10 | 2 | maint |
| 1c79fd5b | This commit updates the **`eslint-plugin-specs`** package to utilize **Hermes** as its JavaScript parser, moving away from Babel. Specifically, the `requireModuleParser` function within `react-native-modules.js` is modified to integrate the Hermes parser plugin and disable any external Babel configuration files. This **tooling update** streamlines the parsing process for linting within this particular plugin. The change ensures that the ESLint plugin correctly processes JavaScript code using the Hermes engine's syntax, improving consistency and performance for spec-related linting. | Mar 10 | 2 | maint |
| f596bb3d | This commit performs a **widespread refactoring** of **Flow type parameter bound syntax** across numerous modules within the React Native codebase. It applies a `transformTypeParamBound` codemod to update type definitions and function signatures in areas such as **Animated components**, **event emitters**, **Jest mocks**, **dev middleware**, and various **utility functions**. This **maintenance task** ensures consistency with modern Flow syntax, improving the maintainability and clarity of the project's type annotations. The changes are purely type-system related and have no impact on runtime behavior or external API surfaces. | Mar 6 | 63 | maint |
| 53cd9cec | This commit executes a **large-scale refactoring** to update **Flow type parameter bound syntax** across the codebase, migrating declarations from `T: Type` to `T extends Type`. Applied via a codemod, this **syntax modernization** impacts a broad array of **Flow type definitions**, including core React Native components like `ReactNativeFeatureFlagsBase` and `virtualized-lists`, web API polyfills, and numerous third-party library type definitions found in `flow-typed/npm/` such as `babel` and `jest`. This **project-wide update** ensures consistency with modern Flow syntax, improving maintainability and compatibility with future Flow tooling. | Mar 6 | 17 | maint |
| 424bfe19 | This commit performs a **maintenance update** by bumping the **Flow type checker configuration** from version `0.301.0` to `0.302.0` within the `.flowconfig` file. This change ensures the project's codebase is now type-checked against the latest stable version of Flow, potentially incorporating new type definitions, stricter checks, or bug fixes introduced in **Flow 0.302.0**. The update affects the entire project's **cross-platform (xplat) codebase** that relies on Flow for static analysis, aligning it with the latest type-checking capabilities. | Feb 19 | 3 | maint |
| f714658f | Update prettier-plugin-hermes-parser in xplat to 0.34.1 (#55409) | Feb 5 | 2 | – |
| 97c92024 | This commit **updates the project's Flow type checker configuration** by bumping the specified version from `0.296.1` to `0.297.0` within the `.flowconfig` file. This **maintenance update** ensures that all subsequent type checks across the codebase will utilize the features, fixes, and stricter rules introduced in **Flow version 0.297.0**. The change impacts the entire **cross-platform development environment**, potentially affecting type inference and error reporting for all Flow-typed files. | Jan 18 | 3 | maint |
| 23aa4ddb | This commit **refactors** and **updates Flow type definitions** for several third-party npm packages, including `react-dom`, `react-test-renderer`, `tinyglobby`, and `yargs`. The changes primarily involve replacing the less precise `mixed` type with `unknown` for improved type safety and consistency across these definitions. Additionally, it standardizes `ReadonlyArray` syntax and adjusts parameter list formatting within the affected **Flow type declarations**. This **maintenance** work enhances the accuracy and robustness of **Flow type checking** for components relying on these libraries, particularly in cross-platform (xplat) contexts. | Jan 17 | 5 | maint |
| 3f56ac08 | This commit **refactors** the Flow type annotations within the **`react-native-codegen` e2e test fixtures** located in `deep_imports/__test_fixtures__`. It systematically updates instances of the deprecated `$ReadOnly` utility type to the modern `Readonly` syntax, and `$ReadOnlyArray` to `ReadonlyArray`. This **maintenance** task was performed via a codemod, ensuring consistency and compatibility with current Flow best practices across various native component and module test definitions. The changes primarily affect the type definitions for `NativeProps`, event types, and method signatures in these test files, aligning them with updated Flow conventions. | Jan 17 | 20 | maint |
| 0d64cf2e | This commit performs a **refactoring** of Flow type annotations within the **e2e test fixtures** of the `react-native-codegen` package. It systematically updates the syntax for readonly types from `$ReadOnly` to `Readonly` across various component, object, and event prop definitions. This **maintenance change**, likely applied via a codemod, ensures the test suite's Flow types are consistent with current Flow best practices. The scope is limited to the `packages/react-native-codegen/e2e/namespaced/__test_fixtures__/` directory, impacting only the internal testing infrastructure and not the runtime behavior of the codegen tool itself. | Jan 17 | 18 | maint |
| cd3a9c55 | This commit performs a significant **refactoring** by **transforming Flow utility types** across the codebase to align with more standard TypeScript equivalents and improve AI integration. Specifically, it replaces custom Flow types like `$NonMaybeType`, `$ReadOnly`, `$ReadOnlyArray`, `$ReadOnlyMap`, `$ReadOnlySet`, `$Keys`, `$Values`, and `mixed` with their standardized counterparts such as `NonNullable`, `Readonly`, `ReadonlyArray`, `ReadonlyMap`, `ReadonlySet`, `keyof`, `Values`, and `unknown`. This widespread change impacts **Flow type definitions** across numerous **React Native libraries and packages**, including `dev-middleware`, various `Libraries` components (e.g., `Animated`, `AppState`, `EventEmitter`), and internal utilities, standardizing the type system. The effort aims to enhance **code consistency and maintainability**, making the codebase more accessible and compatible with modern tooling. | Jan 16 | 30 | maint |
| 60f9bfd5 | This commit performs a **Flow type migration**, specifically transforming the `mixed` type to `unknown` within the project's type definitions. This **refactoring** effort aims to improve **type consistency** with standard TypeScript practices and enhance AI integration for type analysis. The changes primarily affect **Node.js API declarations** in `flow-typed/environment/node.js`, updating types across modules like `crypto`, `fs`, `perf_hooks`, and `timers` to use `unknown` where `mixed` was previously used. This is part of a broader initiative to standardize Flow utility types such as `$NonMaybeType` to `NonNullable` and `$ReadOnly` to `Readonly`. | Jan 15 | 1 | maint |
| 92c32780 | This commit performs a **type migration** by transforming all instances of the Flow utility type `$ReadOnlyArray` to `ReadonlyArray` across the codebase. This **refactoring** is part of a broader initiative to standardize Flow utility types, aiming for **better consistency with TypeScript** and improved AI integration. The change impacts numerous type definitions, function signatures, and class properties within core React Native libraries, including `react-native-codegen`, `react-native-compatibility-check`, `Animated`, `BatchedBridge`, `LogBox`, `StyleSheet`, and various internal modules. This ensures a unified approach to readonly array types, enhancing overall **type consistency** and tooling support. | Jan 14 | 167 | maint |
| 7051a07c | This commit performs a **refactoring** of Flow type annotations across the codebase, specifically migrating instances of `$ReadOnlyArray` to the more standard `ReadonlyArray` utility type. This **type migration** affects numerous **Flow type definitions** within `flow-typed` packages, as well as various **React Native CLI and Codegen packages**, including utility functions, command handlers, and schema definitions. It is part of a broader initiative to modernize Flow types for improved consistency with TypeScript and better AI integration. The change enhances the maintainability and future-proofing of the project's type system without altering runtime behavior. | Jan 14 | 52 | maint |
| 94383613 | This commit performs a **maintenance refactoring** across several **React Native core libraries** and a `scripts` utility. It systematically **updates Flow type annotations**, specifically transforming the deprecated `$Values` utility type to its modern equivalent, `Values`. This change, applied via a `codemod`, ensures **type system consistency** and compatibility with newer Flow versions. The update affects type definitions within **`PermissionsAndroid`**, **`StyleSheet`**, and **`NativeAnimatedHelper`**, among others. This is a purely semantic change to the type system and has **no functional impact** on the runtime behavior of the affected modules. | Jan 13 | 5 | maint |
| ea6884cc | This commit **refactors** the project's **Flow type definitions** by **migrating** instances of `$ReadOnlyMap` to the more standard `ReadonlyMap` utility type. This **type modernization** effort aims to improve consistency with TypeScript conventions and enhance AI integration across the codebase. For example, the type annotation for the `#pages` property in `packages/dev-middleware/src/inspector-proxy/Device.js` has been updated. This **maintenance** task contributes to a more unified and understandable type system. | Jan 13 | 1 | maint |
| 41efc3b5 | This commit performs a widespread **refactoring** across the **React Native codebase** by updating Flow type annotations. Specifically, it **migrates all instances of the `$ReadOnly` utility type to the `Readonly` utility type** for improved consistency and adherence to modern Flow syntax. This change impacts numerous modules, including the **`react-native-codegen` tools**, various **native component and module definitions**, **web API implementations**, **virtualized lists**, and **RNTester examples**. This is a **type system modernization** effort that does not alter runtime behavior but ensures the codebase's type definitions are up-to-date. | Jan 7 | 156 | maint |
| 1cc30dc1 | This commit performs a large-scale **refactoring** of **Flow type definitions** by replacing the custom utility type `$ReadOnly` with the standard `Readonly`. This change is part of an ongoing effort to align Flow's utility types with TypeScript conventions and improve AI integration. It impacts a vast number of files across the **React Native framework**, including core components like `Animated`, `ScrollView`, and `TextInput`, as well as various `flow-typed` npm packages and internal tooling. This **type system migration** enhances consistency and maintainability across the codebase, contributing to better tooling support and future compatibility. | Jan 7 | 175 | maint |
This commit performs a **maintenance update** by upgrading the **Flow type checker version** used in the project from `0.306.1` to `0.307.0`. Specifically, the `.flowconfig` file is modified to reflect this new version, ensuring the project's **type checking system** is aligned with the latest Flow release. This change impacts the entire codebase by potentially introducing new type errors or resolving existing ones, thereby affecting the **development toolchain** and overall code quality enforcement.
This commit performs a **codemod** to update the **Flow type parameter bound syntax** within the **`react-native-codegen` package**. It **refactors** type definitions in `CodegenSchema.js` and parser utilities in `parsers-commons.js`, migrating from the deprecated colon-style bounds to the modern `extends` keyword. Specifically, `Nullable`, `NativeModuleArrayTypeAnnotation`, `unwrapNullable`, and `wrapNullable` are updated to align with current Flow syntax. This **maintenance** task ensures compatibility with newer Flow versions and improves the consistency of type annotations within the codegen tooling, without altering the runtime behavior or generated code.
This commit **updates the `react-native-codegen` package** to switch its JavaScript parsing engine from Babel to **Hermes**. This **tooling change** involves modifying the `package.json` to reflect the new dependency and adding the `babel-plugin-syntax-hermes-parser` to the `.babelrc` configuration. The primary impact is on the internal **code generation process**, ensuring it leverages Hermes for potentially improved parsing performance and compatibility. This is a **maintenance update** for the development tools.
This commit updates the **`eslint-plugin-specs`** package to utilize **Hermes** as its JavaScript parser, moving away from Babel. Specifically, the `requireModuleParser` function within `react-native-modules.js` is modified to integrate the Hermes parser plugin and disable any external Babel configuration files. This **tooling update** streamlines the parsing process for linting within this particular plugin. The change ensures that the ESLint plugin correctly processes JavaScript code using the Hermes engine's syntax, improving consistency and performance for spec-related linting.
This commit performs a **widespread refactoring** of **Flow type parameter bound syntax** across numerous modules within the React Native codebase. It applies a `transformTypeParamBound` codemod to update type definitions and function signatures in areas such as **Animated components**, **event emitters**, **Jest mocks**, **dev middleware**, and various **utility functions**. This **maintenance task** ensures consistency with modern Flow syntax, improving the maintainability and clarity of the project's type annotations. The changes are purely type-system related and have no impact on runtime behavior or external API surfaces.
This commit executes a **large-scale refactoring** to update **Flow type parameter bound syntax** across the codebase, migrating declarations from `T: Type` to `T extends Type`. Applied via a codemod, this **syntax modernization** impacts a broad array of **Flow type definitions**, including core React Native components like `ReactNativeFeatureFlagsBase` and `virtualized-lists`, web API polyfills, and numerous third-party library type definitions found in `flow-typed/npm/` such as `babel` and `jest`. This **project-wide update** ensures consistency with modern Flow syntax, improving maintainability and compatibility with future Flow tooling.
This commit performs a **maintenance update** by bumping the **Flow type checker configuration** from version `0.301.0` to `0.302.0` within the `.flowconfig` file. This change ensures the project's codebase is now type-checked against the latest stable version of Flow, potentially incorporating new type definitions, stricter checks, or bug fixes introduced in **Flow 0.302.0**. The update affects the entire project's **cross-platform (xplat) codebase** that relies on Flow for static analysis, aligning it with the latest type-checking capabilities.
Update prettier-plugin-hermes-parser in xplat to 0.34.1 (#55409)
This commit **updates the project's Flow type checker configuration** by bumping the specified version from `0.296.1` to `0.297.0` within the `.flowconfig` file. This **maintenance update** ensures that all subsequent type checks across the codebase will utilize the features, fixes, and stricter rules introduced in **Flow version 0.297.0**. The change impacts the entire **cross-platform development environment**, potentially affecting type inference and error reporting for all Flow-typed files.
This commit **refactors** and **updates Flow type definitions** for several third-party npm packages, including `react-dom`, `react-test-renderer`, `tinyglobby`, and `yargs`. The changes primarily involve replacing the less precise `mixed` type with `unknown` for improved type safety and consistency across these definitions. Additionally, it standardizes `ReadonlyArray` syntax and adjusts parameter list formatting within the affected **Flow type declarations**. This **maintenance** work enhances the accuracy and robustness of **Flow type checking** for components relying on these libraries, particularly in cross-platform (xplat) contexts.
This commit **refactors** the Flow type annotations within the **`react-native-codegen` e2e test fixtures** located in `deep_imports/__test_fixtures__`. It systematically updates instances of the deprecated `$ReadOnly` utility type to the modern `Readonly` syntax, and `$ReadOnlyArray` to `ReadonlyArray`. This **maintenance** task was performed via a codemod, ensuring consistency and compatibility with current Flow best practices across various native component and module test definitions. The changes primarily affect the type definitions for `NativeProps`, event types, and method signatures in these test files, aligning them with updated Flow conventions.
This commit performs a **refactoring** of Flow type annotations within the **e2e test fixtures** of the `react-native-codegen` package. It systematically updates the syntax for readonly types from `$ReadOnly` to `Readonly` across various component, object, and event prop definitions. This **maintenance change**, likely applied via a codemod, ensures the test suite's Flow types are consistent with current Flow best practices. The scope is limited to the `packages/react-native-codegen/e2e/namespaced/__test_fixtures__/` directory, impacting only the internal testing infrastructure and not the runtime behavior of the codegen tool itself.
This commit performs a significant **refactoring** by **transforming Flow utility types** across the codebase to align with more standard TypeScript equivalents and improve AI integration. Specifically, it replaces custom Flow types like `$NonMaybeType`, `$ReadOnly`, `$ReadOnlyArray`, `$ReadOnlyMap`, `$ReadOnlySet`, `$Keys`, `$Values`, and `mixed` with their standardized counterparts such as `NonNullable`, `Readonly`, `ReadonlyArray`, `ReadonlyMap`, `ReadonlySet`, `keyof`, `Values`, and `unknown`. This widespread change impacts **Flow type definitions** across numerous **React Native libraries and packages**, including `dev-middleware`, various `Libraries` components (e.g., `Animated`, `AppState`, `EventEmitter`), and internal utilities, standardizing the type system. The effort aims to enhance **code consistency and maintainability**, making the codebase more accessible and compatible with modern tooling.
This commit performs a **Flow type migration**, specifically transforming the `mixed` type to `unknown` within the project's type definitions. This **refactoring** effort aims to improve **type consistency** with standard TypeScript practices and enhance AI integration for type analysis. The changes primarily affect **Node.js API declarations** in `flow-typed/environment/node.js`, updating types across modules like `crypto`, `fs`, `perf_hooks`, and `timers` to use `unknown` where `mixed` was previously used. This is part of a broader initiative to standardize Flow utility types such as `$NonMaybeType` to `NonNullable` and `$ReadOnly` to `Readonly`.
This commit performs a **type migration** by transforming all instances of the Flow utility type `$ReadOnlyArray` to `ReadonlyArray` across the codebase. This **refactoring** is part of a broader initiative to standardize Flow utility types, aiming for **better consistency with TypeScript** and improved AI integration. The change impacts numerous type definitions, function signatures, and class properties within core React Native libraries, including `react-native-codegen`, `react-native-compatibility-check`, `Animated`, `BatchedBridge`, `LogBox`, `StyleSheet`, and various internal modules. This ensures a unified approach to readonly array types, enhancing overall **type consistency** and tooling support.
This commit performs a **refactoring** of Flow type annotations across the codebase, specifically migrating instances of `$ReadOnlyArray` to the more standard `ReadonlyArray` utility type. This **type migration** affects numerous **Flow type definitions** within `flow-typed` packages, as well as various **React Native CLI and Codegen packages**, including utility functions, command handlers, and schema definitions. It is part of a broader initiative to modernize Flow types for improved consistency with TypeScript and better AI integration. The change enhances the maintainability and future-proofing of the project's type system without altering runtime behavior.
This commit performs a **maintenance refactoring** across several **React Native core libraries** and a `scripts` utility. It systematically **updates Flow type annotations**, specifically transforming the deprecated `$Values` utility type to its modern equivalent, `Values`. This change, applied via a `codemod`, ensures **type system consistency** and compatibility with newer Flow versions. The update affects type definitions within **`PermissionsAndroid`**, **`StyleSheet`**, and **`NativeAnimatedHelper`**, among others. This is a purely semantic change to the type system and has **no functional impact** on the runtime behavior of the affected modules.
This commit **refactors** the project's **Flow type definitions** by **migrating** instances of `$ReadOnlyMap` to the more standard `ReadonlyMap` utility type. This **type modernization** effort aims to improve consistency with TypeScript conventions and enhance AI integration across the codebase. For example, the type annotation for the `#pages` property in `packages/dev-middleware/src/inspector-proxy/Device.js` has been updated. This **maintenance** task contributes to a more unified and understandable type system.
This commit performs a widespread **refactoring** across the **React Native codebase** by updating Flow type annotations. Specifically, it **migrates all instances of the `$ReadOnly` utility type to the `Readonly` utility type** for improved consistency and adherence to modern Flow syntax. This change impacts numerous modules, including the **`react-native-codegen` tools**, various **native component and module definitions**, **web API implementations**, **virtualized lists**, and **RNTester examples**. This is a **type system modernization** effort that does not alter runtime behavior but ensures the codebase's type definitions are up-to-date.
This commit performs a large-scale **refactoring** of **Flow type definitions** by replacing the custom utility type `$ReadOnly` with the standard `Readonly`. This change is part of an ongoing effort to align Flow's utility types with TypeScript conventions and improve AI integration. It impacts a vast number of files across the **React Native framework**, including core components like `Animated`, `ScrollView`, and `TextInput`, as well as various `flow-typed` npm packages and internal tooling. This **type system migration** enhances consistency and maintainability across the codebase, contributing to better tooling support and future compatibility.