Common

What it is responsible for

Common manages shared framework contracts and input-oriented transformations for Nest applications. Its documented scope includes decorators such as

@Controller()

and

@Injectable()

, while named pipes turn supplied values into parsed or validated forms.

DefaultValuePipe

ParseFilePipe

ParseArrayPipe

, and

ParseBoolPipe

identify entry points for that work;

ValidationPipe

marks validation as part of the same surface. The subsystem also defines the middleware-application contract:

MiddlewareConsumer

applies user-defined middleware to routes, alongside

MiddlewareConfiguration

RouteInfo

, and

NestMiddleware

. The named

ConsoleLogger

and

Logger

place logging within this shared surface.

What it needs, and who needs it

Common needs no dependencies from this repository. The listed consumers—

integration/injector/src/circular-modules

integration/injector/src/circular-properties

integration/inspector/src/circular-modules

integration/scopes/src/inject-inquirer

, and

Integration

—need Common’s contracts and pipe symbols. Without Common, those consumers cannot resolve the subsystem they depend on; references to its decorators, middleware types, logging symbols, serializers, or pipes would be unavailable. No repository dependency is named for Common.

Notable members

DefaultValuePipe

is an identified entry point and, by its name, handles default values.

ParseArrayPipe

is another entry point and names array parsing directly.

MiddlewareConsumer

carries the explicitly documented responsibility: it defines a method for applying user-defined middleware to routes. 353 entities in

packages/common

. 5 other subsystems depend on it, which makes it the 2nd most depended-upon part of this codebase.

What it is made of

Its 353 entities sit in 161 files under

packages/common

: 92 interfaces, 85 functions, 63 constants, 32 type aliases and 81 more.

route-params.decorator.ts

holds 36 of them — more than any other file here.

HttpException

declares 12 methods, the widest surface here.

Where work enters

DefaultValuePipe

—

packages/common/pipes/default-value.pipe.ts

ParseFilePipe

—

packages/common/pipes/file/parse-file.pipe.ts

ParseArrayPipe

—

packages/common/pipes/parse-array.pipe.ts

ParseBoolPipe

—

packages/common/pipes/parse-bool.pipe.ts

How it refuses and fails

6 of its components record a refusal or a failure handler. All 6 of them refuse work outright, under a condition written into the component itself. Their

catch

blocks handle a failure that already happened in 2 places. Of those 2, 1 logs it and continues and 1 turns it into a return value.

Boundaries

5 other subsystems depend on this one —

Circular Modules

Circular Properties

Circular Modules

Inject Inquirer

Integration

. Changing what it exposes changes them. Those 5 hold 11 edges between them, unevenly:

Inject Inquirer

reaches in across 3 edges, against 2 from

Integration

. What they reach is narrower than the folder: 2 of its 353 members carry every inbound edge —

forwardRef

(8) and

Logger

(3).

It depends on no other subsystem in this repository — it is a leaf.

How this code is named

These conventions cover most of the codebase. Learning them is faster than reading an index — each one lets you find any member of its family without looking it up.

Pattern	Where	Count	Examples
`*.interface.ts`	across the repository	67	`type.interface.ts` , `file.interface.ts` , `on-init.interface.ts` , `abstract.interface.ts`
`*.decorator.ts`	across the repository	24	`sse.decorator.ts` , `bind.decorator.ts` , `catch.decorator.ts` , `inject.decorator.ts`
`*.exception.ts`	`packages/common/exceptions/`	23	`gone.exception.ts` , `http.exception.ts` , `conflict.exception.ts` , `forbidden.exception.ts`
`*.util.ts`	across the repository	16	`cli-colors.util.ts` , `forward-ref.util.ts` , `is-log-level.util.ts` , `load-package.util.ts`

What it is responsible for

What it needs, and who needs it

Notable members

What it is made of

Where work enters

How it refuses and fails

Boundaries

How this code is named

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