fix: use import type when possible

this is needed in order to support ```json "verbatimModuleSyntax": true, ``` otherwise, you wind up with errors like: ```shell TS1484: ExpressRuntimeResponder is a type and must be imported using a type-only import when verbatimModuleSyntax is enabled. ```

Author: mnahkies

packages/openapi-code-generator/src/typescript/common/import-builder.spec.ts

@@ -12,17 +12,17 @@ describe("typescript/common/import-builder", () => {
  it("can import individual exports", () => {
  const builder = new ImportBuilder()
 
- builder.addSingle("Cat", "./models.ts")
- builder.addSingle("Dog", "./models.ts")
+ builder.addSingle("Cat", "./models.ts", false)
+ builder.addSingle("Dog", "./models.ts", false)
 
  expect(builder.toString()).toBe("import {Cat, Dog} from './models'")
  })
 
  it("can import a whole module, and individual exports", () => {
  const builder = new ImportBuilder()
 
- builder.addSingle("Next", "koa")
- builder.addSingle("Context", "koa")
+ builder.addSingle("Next", "koa", false)
+ builder.addSingle("Context", "koa", false)
  builder.addModule("koa", "koa")
 
  expect(builder.toString()).toBe("import koa, {Context, Next} from 'koa'")
@@ -32,33 +32,44 @@ describe("typescript/common/import-builder", () => {
  it("same directory", () => {
  const builder = new ImportBuilder({filename: "./foo/example.ts"})
 
- builder.addSingle("Cat", "./foo/models.ts")
+ builder.addSingle("Cat", "./foo/models.ts", false)
 
  expect(builder.toString()).toBe("import {Cat} from './models'")
  })
 
  it("parent directory", () => {
  const builder = new ImportBuilder({filename: "./foo/example.ts"})
 
- builder.addSingle("Cat", "./models.ts")
+ builder.addSingle("Cat", "./models.ts", false)
 
  expect(builder.toString()).toBe("import {Cat} from '../models'")
  })
 
  it("child directory", () => {
  const builder = new ImportBuilder({filename: "./example.ts"})
 
- builder.addSingle("Cat", "./foo/models.ts")
+ builder.addSingle("Cat", "./foo/models.ts", false)
 
  expect(builder.toString()).toBe("import {Cat} from './foo/models'")
  })
 
  it("sibling directory", () => {
  const builder = new ImportBuilder({filename: "./foo/example.ts"})
 
- builder.addSingle("Cat", "./bar/models.ts")
+ builder.addSingle("Cat", "./bar/models.ts", false)
 
  expect(builder.toString()).toBe("import {Cat} from '../bar/models'")
  })
  })
+
+ describe("type imports", () => {
+ it("can import types", () => {
+ const builder = new ImportBuilder()
+
+ builder.addSingle("Cat", "./models.ts", false)
+ builder.addSingle("Dog", "./models.ts", true)
+
+ expect(builder.toString()).toBe("import {Cat, type Dog} from './models'")
+ })
+ })
 })

packages/openapi-code-generator/src/typescript/common/import-builder.ts

@@ -1,27 +1,37 @@
 import path from "node:path"
 
 export class ImportBuilder {
- private readonly imports: Record<string, Set<string>> = {}
+ private readonly imports: Record<
+ string,
+ {values: Set<string>; types: Set<string>}
+ > = {}
  private readonly importAll: Record<string, string> = {}
 
  constructor(private readonly unit?: {filename: string}) {}
 
  from(from: string) {
- return {
- add: (...names: string[]): this => {
+ const chain = {
+ add: (...names: string[]) => {
  for (const it of names) {
- this.addSingle(it, from)
+ this.addSingle(it, from, false)
  }
- return this
+ return chain
  },
- all: (name: string): this => {
+ addType: (...names: string[]) => {
+ for (const it of names) {
+ this.addSingle(it, from, true)
+ }
+ return chain
+ },
+ all: (name: string) => {
  this.addModule(name, from)
- return this
+ return chain
  },
  }
+ return chain
  }
 
- addSingle(name: string, from: string): void {
+ addSingle(name: string, from: string, isType: boolean): void {
  if (!name) {
  throw new Error(`cannot addSingle with name '${name}'`)
  }
@@ -30,7 +40,7 @@ export class ImportBuilder {
  throw new Error(`cannot addSingle with from '${from}'`)
  }
 
- this.add(name, from, false)
+ this.add(name, from, false, isType)
  }
 
  addModule(name: string, from: string): void {
@@ -42,7 +52,8 @@ export class ImportBuilder {
  throw new Error(`cannot addModule with from '${from}'`)
  }
 
- this.add(name, from, true)
+ // todo: add support for importing whole module as a type
+ this.add(name, from, true, false)
  }
 
  static merge(
@@ -51,42 +62,71 @@ export class ImportBuilder {
  ): ImportBuilder {
  const result = new ImportBuilder(unit)
 
- // biome-ignore lint/complexity/noForEach: todo
- builders.forEach((builder) => {
- // biome-ignore lint/complexity/noForEach: todo
- Object.entries(builder.imports).forEach(([key, value]) => {
- // biome-ignore lint/suspicious/noAssignInExpressions: todo
- const imports = (result.imports[key] = result.imports[key] ?? new Set())
+ for (const builder of builders) {
+ for (const [key, {values, types}] of Object.entries(builder.imports)) {
+ if (!result.imports[key]) {
+ result.imports[key] = {
+ values: new Set(),
+ types: new Set(),
+ }
+ }
+
+ const imports = result.imports[key]
 
- for (const it of value) {
- imports.add(it)
+ for (const it of values) {
+ imports.values.add(it)
  }
- })
+ for (const it of types) {
+ imports.types.add(it)
+ }
+ }
 
- // biome-ignore lint/complexity/noForEach: todo
- Object.entries(builder.importAll).forEach(([key, value]) => {
+ for (const [key, value] of Object.entries(builder.importAll)) {
  if (result.importAll[key] && result.importAll[key] !== value) {
  throw new Error("cannot merge imports with colliding importAlls")
  }
 
  result.importAll[key] = value
- })
- })
+ }
+ }
 
  return result
  }
 
- private add(name: string, from: string, isAll: boolean): void {
+ private add(
+ name: string,
+ from: string,
+ isAll: boolean,
+ isType: boolean,
+ ): void {
  // biome-ignore lint/style/noParameterAssign: normalization
  from = this.normalizeFrom(from)
- // biome-ignore lint/suspicious/noAssignInExpressions: init
- const imports = (this.imports[from] =
- this.imports[from] ?? new Set<string>())
+
+ if (!this.imports[from]) {
+ this.imports[from] = {
+ values: new Set(),
+ types: new Set(),
+ }
+ }
+
+ let imports = this.imports[from]
+
+ if (!imports) {
+ imports = {
+ values: new Set(),
+ types: new Set(),
+ }
+ this.imports[from] = imports
+ }
 
  if (isAll) {
  this.importAll[from] = name
  } else {
- imports.add(name)
+ if (isType) {
+ imports.types.add(name)
+ } else {
+ imports.values.add(name)
+ }
  }
  }
 
@@ -140,10 +180,19 @@ export class ImportBuilder {
  )
  .sort()
  .map((from) => {
- // biome-ignore lint/style/noNonNullAssertion: todo
- const individualImports = Array.from(this.imports[from]!.values())
- .sort()
- .filter(hasImport)
+ const valueImports = Array.from(
+ (this.imports[from]?.values ?? new Set()).values(),
+ )
+ const typeImports = Array.from(
+ (this.imports[from]?.types ?? new Set()).values(),
+ )
+
+ const individualImports = valueImports
+ .map((it) => ({name: it, isType: false}))
+ .concat(typeImports.map((it) => ({name: it, isType: true})))
+ .sort((a, b) => (a.name < b.name ? -1 : 1))
+ .filter((it) => hasImport(it.name))
+ .map((it) => (it.isType ? `type ${it.name}` : it.name))
  .join(", ")
 
  const importAll = this.importAll[from]

packages/openapi-code-generator/src/typescript/common/schema-builders/abstract-schema-builder.ts

@@ -65,7 +65,7 @@ export abstract class AbstractSchemaBuilder<
  this.referenced[name] = reference
 
  if (this.imports) {
- this.imports.addSingle(name, this.filename)
+ this.imports.addSingle(name, this.filename, false)
  }
 
  return name
@@ -78,7 +78,7 @@ export abstract class AbstractSchemaBuilder<
 
  this.parent?.addStaticSchema(name)
  this.referencedStaticSchemas.add(name)
- this.imports?.addSingle(name, this.filename)
+ this.imports?.addSingle(name, this.filename, false)
 
  return name
  }

packages/openapi-code-generator/src/typescript/common/schema-builders/zod-v3-schema-builder.ts

@@ -224,6 +224,7 @@ export class ZodV3Builder extends AbstractSchemaBuilder<
  this.schemaBuilderImports.addSingle(
  "UnknownEnumNumberValue",
  "./models",
+ false,
  )
  return [
  this.union([
@@ -275,6 +276,7 @@ export class ZodV3Builder extends AbstractSchemaBuilder<
  this.schemaBuilderImports.addSingle(
  "UnknownEnumStringValue",
  "./models",
+ false,
  )
  return this.union([
  this.stringEnum(model),

packages/openapi-code-generator/src/typescript/common/schema-builders/zod-v4-schema-builder.ts

@@ -227,6 +227,7 @@ export class ZodV4Builder extends AbstractSchemaBuilder<
  this.schemaBuilderImports.addSingle(
  "UnknownEnumNumberValue",
  "./models",
+ false,
  )
  return [
  this.union([
@@ -278,6 +279,7 @@ export class ZodV4Builder extends AbstractSchemaBuilder<
  this.schemaBuilderImports.addSingle(
  "UnknownEnumStringValue",
  "./models",
+ false,
  )
  return this.union([
  this.stringEnum(model),

packages/openapi-code-generator/src/typescript/common/type-builder.ts

@@ -77,15 +77,15 @@ export class TypeBuilder implements ICompilable {
 
  const name = this.getTypeNameFromRef({$ref})
 
- this.imports?.addSingle(name, this.filename)
+ this.imports?.addSingle(name, this.filename, true)
 
  return name
  }
 
  protected addStaticType(name: StaticType): string {
  this.parent?.addStaticType(name)
  this.referencedStaticTypes.add(name)
- this.imports?.addSingle(name, this.filename)
+ this.imports?.addSingle(name, this.filename, true)
 
  return name
  }

packages/openapi-code-generator/src/typescript/server/typescript-express/typescript-express-router-builder.ts

@@ -33,17 +33,17 @@ export class ExpressRouterBuilder extends AbstractRouterBuilder {
  protected buildImports(): void {
  this.imports
  .from("express")
- .add("Router", "Request", "Response", "NextFunction")
+ .add("Router")
+ .addType("Request", "Response", "NextFunction")
 
  this.imports.from("express").all("express")
 
  this.imports
  .from("@nahkies/typescript-express-runtime/server")
- .add(
+ .add("ExpressRuntimeResponse", "SkipResponse")
+ .addType(
  "ExpressRuntimeResponder",
- "ExpressRuntimeResponse",
  "Params",
- "SkipResponse",
  "StatusCode",
  "StatusCode1xx",
  "StatusCode2xx",

packages/openapi-code-generator/src/typescript/server/typescript-express/typescript-express-server-builder.ts

@@ -12,7 +12,8 @@ export class ExpressServerBuilder implements ICompilable {
  ) {
  this.imports
  .from("@nahkies/typescript-express-runtime/server")
- .add("startServer", "ServerConfig")
+ .add("startServer")
+ .addType("ServerConfig")
  }
 
  toString(): string {

packages/openapi-code-generator/src/typescript/server/typescript-koa/typescript-koa-router-builder.ts

@@ -34,28 +34,24 @@ export class KoaRouterBuilder extends AbstractRouterBuilder {
  // todo: unsure why, but adding an export at `.` of index.ts doesn't work properly
  this.imports
  .from("@nahkies/typescript-koa-runtime/server")
- .add(
+ .add("KoaRuntimeResponse", "SkipResponse", "startServer")
+ .addType(
  "KoaRuntimeResponder",
- "KoaRuntimeResponse",
  "Params",
  "Response",
- "ServerConfig",
- "SkipResponse",
  "StatusCode",
  "StatusCode2xx",
  "StatusCode3xx",
  "StatusCode4xx",
  "StatusCode5xx",
- "startServer",
  )
 
  this.imports
  .from("@nahkies/typescript-koa-runtime/errors")
  .add("KoaRuntimeError", "RequestInputType")
 
  this.imports.from("koa").add("Next")
- this.imports.addModule("KoaRouter", "@koa/router")
- this.imports.from("@koa/router").add("RouterContext")
+ this.imports.from("@koa/router").addType("RouterContext").all("KoaRouter")
 
  const schemaBuilderType = this.schemaBuilder.type
 

packages/openapi-code-generator/src/typescript/server/typescript-koa/typescript-koa-server-builder.ts

@@ -12,7 +12,8 @@ export class KoaServerBuilder implements ICompilable {
  ) {
  this.imports
  .from("@nahkies/typescript-koa-runtime/server")
- .add("startServer", "ServerConfig")
+ .add("startServer")
+ .addType("ServerConfig")
  }
 
  toString(): string {