printer

GraphQL Schema Printer Module

This module provides functionality for printing GraphQL schema types into Markdown documentation. It includes utilities for handling various GraphQL types, custom directives, and formatting options.

Printer

Defined in: printer-legacy/src/printer.ts:184

The Printer class implements the core functionality for generating Markdown documentation from GraphQL schema types.

Remarks

This class provides static methods for rendering different components of the documentation:

• Headers and frontmatter
• Type descriptions and code blocks
• Custom directives and metadata
• Examples and relations

Example

const printer = new Printer();
await printer.init(schema, "/docs", "graphql", options);
const docs = printer.printType("Query", queryType);

Implements

• IPrinter

Constructors

Constructor

new Printer(): Printer;

Returns

Printer

Properties

printDecorators

readonly static printDecorators: (type, options) => PageSections;

Defined in: printer-legacy/src/printer.ts:193

Prints predicate-driven decorators

Prints every decorator declared in the print options, excluding those targeting a named slot (position: { into }) — those are not part of the page's section order and are printed separately, into their slot.

Every declared decorator yields an entry, so that composition hooks can restore one which rendered no content. Decorators with a reserved or repeated id are dropped.

Parameters

type

unknown

the GraphQL type being printed.

options

PrintTypeOptions

the print options in effect.

Returns

PageSections

a map of decorator id to rendered section, empty when none is declared.

printDescription

readonly static printDescription: (type, options, noText?) => string | MDXString;

Defined in: printer-legacy/src/printer.ts:188

Prints type descriptions

Prints the complete description for a GraphQL type, including deprecation warnings and custom directives.

Parameters

type

unknown

The GraphQL type to document

options

PrintTypeOptions

Configuration options for printing

noText?

string

Optional text to display when no description exists

Returns

string | MDXString

Combined description, deprecation notices, and custom directives as MDX content

Accessors

eventEmitter

Get Signature

get static eventEmitter(): Maybe<PrinterEventEmitter>;

Defined in: printer-legacy/src/printer.ts:213

Optional event emitter for print events. When set, the printer will emit events before/after printCode and printType, allowing external code to intercept and modify the output.

Returns

Maybe<PrinterEventEmitter>

Set Signature

set static eventEmitter(eventEmitter): void;

Defined in: printer-legacy/src/printer.ts:228

Parameters

eventEmitter

Maybe<PrinterEventEmitter>

Returns

void

mdxDeclaration

Get Signature

get static mdxDeclaration(): Readonly<Maybe<string>>;

Defined in: printer-legacy/src/printer.ts:220

Prints mdx modules import declaration

Returns

Readonly<Maybe<string>>

Set Signature

set static mdxDeclaration(mdxDeclaration): void;

Defined in: printer-legacy/src/printer.ts:232

Parameters

mdxDeclaration

Readonly<Maybe<string>>

Returns

void

options

Get Signature

get static options(): Readonly<Maybe<PrintTypeOptions>>;

Defined in: printer-legacy/src/printer.ts:204

Global printer configuration options

Returns

Readonly<Maybe<PrintTypeOptions>>

Set Signature

set static options(options): void;

Defined in: printer-legacy/src/printer.ts:224

Parameters

options

Readonly<Maybe<PrintTypeOptions>>

Returns

void

Methods

init()

static init(
   schema,
   baseURL?,
   linkRoot?,
   options?,
   formatter?,
   mdxDeclaration?,
   eventEmitter?
): Promise<void>;

Defined in: printer-legacy/src/printer.ts:247

Initializes the printer with the given schema and configuration.

Parameters

schema

Maybe<GraphQLSchema>

GraphQL schema to generate documentation for

baseURL?

Maybe<string> = "schema"

Base URL path for documentation, e.g. '/docs'

linkRoot?

Maybe<string> = "/"

Root path for generating links between types

options?

PrinterInitOptions = DEFAULT_INIT_OPTIONS

Configuration options for the printer

formatter?

Partial<Formatter>

Optional formatter functions for customizing output format

mdxDeclaration?

Maybe<string>

Optional MDX import declaration

eventEmitter?

Maybe<PrinterEventEmitter>

Optional event emitter for print events interception

Returns

Promise<void>

printCode()

readonly static printCode(type, options): string;

Defined in: printer-legacy/src/printer.ts:335

Prints the GraphQL type definition as code block

Parameters

type

unknown

GraphQL type to print

options

PrintTypeOptions

Printer configuration options

Returns

string

Formatted code block string with type definition

printCodeAsync()

readonly static printCodeAsync(
   type,
   typeName,
   options
): Promise<string>;

Defined in: printer-legacy/src/printer.ts:391

Prints the GraphQL type definition as code block with event emission support.

Parameters

type

unknown

GraphQL type to print

typeName

string

Name of the type being printed

options

PrintTypeOptions

Printer configuration options

Returns

Promise<string>

Promise resolving to formatted code block string with type definition

Remarks

This async version emits events before and after code generation:

• print:beforePrintCode - Emitted before generating code (can modify inputs or prevent default)
• print:afterPrintCode - Emitted after generating code (can modify output)

Event handlers can:

• Modify event.data.options in BEFORE to affect code generation
• Call event.preventDefault() in BEFORE to skip default generation and provide custom output
• Modify event.output in AFTER to change the final result

printExample()

readonly static printExample(type, options): Maybe<PageSection>;

Defined in: printer-legacy/src/printer.ts:436

Prints example usage of the type if available

Parameters

type

unknown

GraphQL type to generate example for

options

PrintTypeOptions

Printer configuration options

Returns

Maybe<PageSection>

Example page section or undefined when no example is available

printHeader()

readonly static printHeader(
   id,
   title,
   options
): string;

Defined in: printer-legacy/src/printer.ts:314

Prints the header section of a type documentation

Parameters

id

string

Unique identifier for the type

title

string

Display title for the type

options

PrintTypeOptions

Printer configuration options

Returns

string

Formatted header string with optional frontmatter

printMetaTags()

readonly static printMetaTags(_type, options): string | MDXString;

Defined in: printer-legacy/src/printer.ts:497

Prints HTML meta tags for the documentation

Parameters

_type

unknown

GraphQL type (unused)

options

PrintTypeOptions

Printer configuration options containing metatags

Returns

string | MDXString

Formatted HTML meta tags string

printRelations()

readonly static printRelations(type, options): string | MDXString;

Defined in: printer-legacy/src/printer.ts:483

Prints related type information

Parameters

type

unknown

GraphQL type to find relations for

options

PrintTypeOptions

Printer configuration options

Returns

string | MDXString

Formatted relations section as MDX or plain string

printType()

readonly static printType(
   name,
   type,
   options?
): Promise<Maybe<MDXString>>;

Defined in: printer-legacy/src/printer.ts:547

Main method to print complete documentation for a GraphQL type

Parameters

name

Maybe<string>

Name identifier for the type

type

unknown

GraphQL type to generate documentation for

options?

Maybe<Partial<PrintTypeOptions>>

Optional printer configuration options

Returns

Promise<Maybe<MDXString>>

Complete documentation as MDX string or undefined if type should be skipped

Example

const doc = await Printer.printType("User", UserType, {
  frontMatter: true,
});

Remarks

The method combines multiple sections:

• Header with frontmatter
• Meta tags
• Description
• Code definition
• Custom directives
• Type metadata
• Example usage
• Related types

When an event emitter is configured, emits events:

• print:beforePrintType - Before generating documentation
• print:beforeComposePageType - Before composing section order and final page output
• print:afterPrintType - After generating documentation (output can be modified)

printTypeMetadata()

readonly static printTypeMetadata(type, options): Maybe<
  | PageSection
  | PageSection[]>;

Defined in: printer-legacy/src/printer.ts:450

Prints metadata information for a GraphQL type

Parameters

type

unknown

GraphQL type to print metadata for

options

PrintTypeOptions

Printer configuration options

Returns

Maybe< | PageSection | PageSection[]>

Metadata section (or section list) for supported types, otherwise undefined