typeconv is an extremely fast silver bullet type conversion utility.
It converts between any of its supported types, bidirectionally.
typeconv lets you convert between type systems which have core-types converters, such as JSON Schema, TypeScript, GraphQL, Open API and SureType. This package can be used as an API programatically or as an application (installed in node_modules/.bin or by using e.g. npx).
By taking advantage of the core-types (npm) toolbox for generic type handling, typeconv can convert and maintain source code location information, comments, descriptions etc. when converting between the different type systems. It is using the following converter packages:
These type systems don't share the same set of types and constraints. For example, JSON Schema has value constraints (like "a string must be longer than 5 characters") and GraphQL doesn't have null or key-value objects as a first-class type. Convertions will therefore produce the smallest common denominator of type information, but still be very useful. See core-types for more information on its supported types, and why not implement a new conversion package yourself!
TL;DR CLI
Convert files from TypeScript ("ts") to GraphQL ("gql"), put the generated files in the gql-schemas directory in the same directory structure as the source files:
$ typeconv -f ts -t gql -o gql-schemas 'types/**/*.ts'This generates gql-schemas/*.graphql for each .ts file in types/ (and sub-directories).
Note that when using glob patterns, put them in quotes to not have the shell try to expand the pattern - typeconv will do it a lot better!
SureType
When converting from SureType, typeconv will extract all exported validators.
Versions
Since v2:
- The package is a pure ESM module, no more CommonJS support. This will likely not affect CLI usages.
- Node 12 support is dropped.
Contents
Conversion example
Converting the following JSON Schema:
{
"definitions": {
"User": {
"type": "object",
"title": "User type",
"description": "This type holds the user information, such as name",
"properties": { "name": { "type": "string", "title": "The real name" } },
"required": [ "name" ]
},
"ChatLine": {
"type": "object",
"title": "A chat line",
"properties": {
"user": { "$ref": "#/definitions/User" },
"line": { "type": "string" }
},
"required": [ "user", "line" ]
}
}
}... to TypeScript will produce:
/*User type
This type holds the user information, such as name*/
export interface User {
/*The real name*/
name: string;
}
/*A chat line*/
export interface ChatLine {
user: User;
line: string;
}or if converted into TypeScript declarations (for .d.ts files), export interface will be export declare interface.
... and to GraphQL will produce:
"""
# User type
This type holds the user information, such as name
"""
type User {
"The real name"
name: String!
}
"A chat line"
type ChatLine {
user: User!
line: String!
}Conversions are bi-directional, so any of these type systems can convert to any other.
Usage
Command line
You can depend on typeconv, and if so, you'll have node_modules/.bin/typeconv installed. Or you run it with on-the-fly installation using npx, as npx typeconv args....
Use -f (or --from-type) to specify from which type system to convert, and -t (or --to-type) to specify which type system to convert to. Other options can be used to configure each configuration (both the from and the to) and these options are usually only available for a specific type system.
The types supported are gql (GraphQL), ts (TypeScript), jsc (JSON Schema), oapi (Open API) and st (SureType).
$ typeconv --help
Usage: typeconv [options] file ...
Options:
-h, --help Print (this) help screen
--version Print the program version
-v, --verbose Verbose informational output (default: false)
--dry-run Prepare and perform conversion, but write no output (default: false)
--(no-)hidden Include hidden files, i.e. files in .gitignore,
files beginning with '.' and the '.git' directory
(default: true)
-f, --from-type <type> Type system to convert from
Values:
ts TypeScript
jsc JSON Schema
gql GraphQL
oapi Open API
st SureType
ct core-types
-t, --to-type <type> Type system to convert to
Values:
ts TypeScript
jsc JSON Schema
gql GraphQL
oapi Open API
st SureType
ct core-types
--(no-)shortcut Shortcut conversion if possible (bypassing core-types).
This is possible between SureType, JSON Schema and Open API
to preserve all features which would otherwise be erased.
(default: true)
-o, --output-directory <dir> Output directory. Defaults to the same as the input files.
-O, --output-extension <ext> Output filename extension to use.
Defaults to 'ts'/'d.ts', 'json', 'yaml' and 'graphql'.
Use '-' to not save a file, but output to stdout instead.
--(no-)strip-annotations Removes all annotations (descriptions, comments, ...) (default: false)
TypeScript
--(no-)ts-declaration Output TypeScript declarations (default: false)
--(no-)ts-disable-lint-header Output comments for disabling linting (default: true)
--(no-)ts-descriptive-header Output the header comment (default: true)
--(no-)ts-use-unknown Use 'unknown' type instead of 'any' (default: true)
--ts-non-exported <method> Strategy for non-exported types (default: include-if-referenced)
Values:
fail Fail conversion
ignore Don't include non-exported types,
even if referenced
include Include non-exported types
inline Don't include non-exported types,
inline them if necessary.
Will fail on cyclic types
include-if-referenced Include non-exported types only if they
are referenced from exported types
--ts-namespaces <method> Namespace strategy. (default: ignore)
Values:
ignore Ignore namespaces entirely (default).
- When converting from TypeScript, types in namespaces
aren't exported.
- When converting to TypeScript, no attempt to
reconstruct namespaces is performed.
hoist When converting from TypeScript, hoist types inside
namespaces to top-level, so that the types are
included, but without their namespace.
This can cause conflicts, in which case deeper
declarations will be dropped in favor of more top-
level declarations.
In case of same-level (namespace depth) declarations
with the same name, only one will be exported in a
non-deterministic manner.
dot When converting from TypeScript, join the namespaces
and the exported type with a dot (.).
When converting to TypeScript, try to reconstruct
namespaces by splitting the name on dot (.).
underscore When converting from TypeScript, join the namespaces
and the exported type with an underscore (_).
When converting to TypeScript, try to reconstruct
namespaces by splitting the name on underscore (_).
reconstruct-all When converting to TypeScript, try to reconstruct
namespaces by splitting the name on both dot and
underscore.
GraphQL
--gql-unsupported <method> Method to use for unsupported types
Values:
ignore Ignore (skip) type
warn Ignore type, but warn
error Throw an error
--gql-null-typename <name> Custom type name to use for null
Open API
--oapi-format <fmt> Output format for Open API (default: yaml)
Values:
json JSON
yaml YAML ('yml' is also allowed)
--oapi-title <title> Open API title to use in output document.
Defaults to the input filename.
--oapi-version <version> Open API document version to use in output document. (default: 1)
SureType
--st-ref-method <method> SureType reference export method (default: provided)
Values:
no-refs Don't ref anything, inline all types
provided Reference types that are explicitly exported
ref-all Ref all provided types and those with names
--st-missing-ref <method> What to do when detecting an unresolvable reference (default: warn)
Values:
ignore Ignore; skip type or cast to any
warn Same as 'ignore', but warn
error Fail conversion
--(no-)st-inline-types Inline pretty typescript types aside validator code (default: true)
--(no-)st-export-type Export the deduced types (or the pretty types,
depending on --st-inline-types)
(default: true)
--(no-)st-export-schema Export validator schemas (default: false)
--(no-)st-export-validator Export regular validators (default: true)
--(no-)st-export-ensurer Export 'ensurer' validators (default: true)
--(no-)st-export-type-guard Export type guards (is* validators) (default: true)
--(no-)st-use-unknown Use 'unknown' type instead of 'any' (default: true)
--(no-)st-forward-schema Forward the JSON Schema, and create an untyped validator schema
with the raw JSON Schema under the hood
(default: false)
As API
To convert from one type system to another, you create a reader for the type system to convert from and a writer for the type system to convert to. The readers and writers for the different type systems have their own set of options. Some have no options (like the JSON Schema reader), some require options (like the Open API writer).
makeConverter
Making a converter is done using makeConverter(reader, writer, options?), which takes a reader and a writer, and optionally options:
cwd (string)
The current working directory, only useful when working with files.
simplify (boolean) (default true)
When simplify is true, the converter will let core-types compress the types after having converted from {reader} format to core-types. This is usually recommended, but may cause some annotations (comments) to be dropped.
map (ConvertMapFunction)
Custom map function for transforming each type after it has been converted from the source type (and after it has been simplified), but before it's written to the target type system.
Type: (node: NamedType, index: number, array: ReadonlyArray<NamedType>) => NamedType
(NamedType ref)
If filter is used as well, this runs before filter.
If transform is used as well, this runs before transform.
filter (ConvertFilterFunction)
Custom filter function for filtering types after they have been converted from the source type.
Type: (node: NamedType, index: number, array: ReadonlyArray<NamedType>) => boolean
(NamedType ref)
If map is used as well, this runs after map.
If transform is used as well, this runs before transform.
transform (ConvertTransformFunction)
Custom filter function for filtering types after they have been converted from the source type.
Type: ( doc: NodeDocument ) => NodeDocument
(NodeDocument ref)
If map is used as well, this runs after map.
If filter is used as well, this runs after filter.
shortcut (boolean) (default true)
Shortcut reader and writer if possible (bypassing core-types).
Basic example conversion
import {
getTypeScriptReader,
getOpenApiWriter,
makeConverter,
} from 'typeconv'
const reader = getTypeScriptReader( );
const writer = getOpenApiWriter( { format: 'yaml', title: 'My API', version: 'v1' } );
const { convert } = makeConverter( reader, writer );
const { data } = await convert( { data: "export type Foo = string | number;" } );
data; // This is the Open API yaml as a stringJSON Schema
There are two exported functions for JSON Schema:
import { getJsonSchemaReader, getJsonSchemaWriter } from 'typeconv'
const reader = getJsonSchemaReader( );
const writer = getJsonSchemaWriter( );They don't have any options.
typeconv expects the JSON Schema to contain definitions, i.e. to be in the form:
JSON Schema
{
"definitions": {
"User": {
"type": "object",
"properties": { "name": { "type": "string" } },
"required": [ "name" ]
},
"ChatLine": {
"type": "object",
"properties": {
"user": { "$ref": "#/definitions/User" },
"line": { "type": "string" }
},
"required": [ "user", "line" ]
}
}
}typeconv doesn't support external references (to other files). If you have that, you need to use a reference parser and merge it into one inline-referenced file before using typeconv.
Open API
Converting to or from Open API can be done with both JSON and YAML. The default is JSON.
When reading, if the filename ends with .yml or .yaml, typeconv will interpret the input as YAML.
Writing however, is decided in the writer factory and provided to getOpenApiWriter.
import { getOpenApiReader, getOpenApiWriter } from 'typeconv'
const reader = getOpenApiReader( );
const writer = getOpenApiWriter( {
format: 'yaml',
title: 'My API',
version: 'v1',
schemaVersion: '3.0.0',
} );The options to getOpenApiWriter is:
interface {
format?: string;
title: string;
version: string;
schemaVersion?: string;
}TypeScript
TypeScript conversion is done using:
import { getTypeScriptReader, getTypeScriptWriter } from 'typeconv'
const reader = getTypeScriptReader( );
const writer = getTypeScriptWriter( );Both these take an optional argument.
The getTypeScriptReader takes an optional
FromTsOptions
object from core-types-ts, although warn isn't necessary since it's set by typeconv internally.
The getTypeScriptWriter takes an optional
ToTsOptions
object from core-types-ts, although warn, filename, sourceFilename, userPackage and userPackageUrl aren't necessary since they're set by typeconv internally.
GraphQL
GraphQL conversion is done using;
import { getGraphQLReader, getGraphQLWriter } from 'typeconv'
const reader = getGraphQLReader( );
const writer = getGraphQLWriter( );Both these take an optional argument.
The getGraphQLReader takes an optional
GraphqlToCoreTypesOptions
object from core-types-graphql, although warn isn't necessary since it's set by typeconv internally.
The getGraphQLWriter takes an optional
CoreTypesToGraphqlOptions
object from core-types-graphql, although warn, filename, sourceFilename, userPackage and userPackageUrl aren't necessary since they're set by typeconv internally.
SureType
SureType conversion is done using;
import { getSureTypeReader, getSureTypeWriter } from 'typeconv'
const reader = getSureTypeReader( );
const writer = getSureTypeWriter( );Both these take an optional argument from the core-types-suretype package.
The getSureTypeReader takes an optional
SuretypeToJsonSchemaOptions.
The getSureTypeWriter takes an optional
JsonSchemaToSuretypeOptions.