Add definitionType option

This option allows users to control whether the output definition are typescript types or interfaces
mogzol · Dec 12, 2023 · 2a89ba2 · 2a89ba2
1 parent bc6eddc
commit 2a89ba2
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Showing 8 changed files with 100 additions and 12 deletions.
diff --git a/README.md b/README.md
@@ -56,6 +56,7 @@ Note that `bigint` types don't have a default `toJSON` method, so the above assu
 | typePrefix        |                        `string`                        |                                    `""`                                    | Prefix to add to [type](https://www.prisma.io/docs/concepts/components/prisma-schema/data-model#defining-composite-types) types (mongodb only).                                                                  |
 | typeSuffix        |                        `string`                        |                                    `""`                                    | Suffix to add to [type](https://www.prisma.io/docs/concepts/components/prisma-schema/data-model#defining-composite-types) types (mongodb only).                                                                  |
 | headerComment     |                        `string`                        | `"This file was auto-generated by prisma-generator-typescript-interfaces"` | Sets the header comment added to the top of the generated file. Set this to an empty string to disable the header comment. Supports multiple lines with `"\n"`.                                                  |
+| definitionType    |                `"interface" \| "type"`                 |                               `"interface"`                                | Controls how the model definitions are generated. `"interface"` will create Typescript interfaces, `"type"` will create Typescript types.                                                                        |
 | enumType          |               `"stringUnion" \| "enum"`                |                              `"stringUnion"`                               | Controls how enums are generated. `"enum"` will create Typescript enums, `"stringUnion"` will create union types with all the enum values.                                                                       |
 | dateType          |            `"Date" \| "string" \| "number"`            |                                  `"Date"`                                  | The type to use for DateTime model fields.                                                                                                                                                                       |
 | bigIntType        |           `"bigint" \| "string" \| "number"`           |                                 `"bigint"`                                 | The type to use for BigInt model fields.                                                                                                                                                                         |

diff --git a/generator.ts b/generator.ts
@@ -15,6 +15,7 @@ interface Config {
   typePrefix: string;
   typeSuffix: string;
   headerComment: string;
+  definitionType: "interface" | "type";
   enumType: "stringUnion" | "enum";
   dateType: "Date" | "string" | "number";
   bigIntType: "bigint" | "string" | "number";
@@ -48,6 +49,9 @@ const CUSTOM_TYPES: Record<string, string> = {
 
 function validateConfig(config: Config) {
   const errors: string[] = [];
+  if (!["interface", "type"].includes(config.definitionType)) {
+    errors.push(`Invalid definitionType: ${config.definitionType}`);
+  }
   if (!["stringUnion", "enum"].includes(config.enumType)) {
     errors.push(`Invalid enumType: ${config.enumType}`);
   }
@@ -143,7 +147,15 @@ function getModelTs(
     .join("\n");
 
   const name = modelNameMap.get(modelData.name) ?? typeNameMap.get(modelData.name);
-  return `export interface ${name} {\n${fields}\n}`;
+
+  switch (config.definitionType) {
+    case "interface":
+      return `export interface ${name} {\n${fields}\n}`;
+    case "type":
+      return `export type ${name} = {\n${fields}\n};`;
+    default:
+      throw new Error(`Unknown definitionType: ${config.definitionType}`);
+  }
 }
 
 generatorHandler({
@@ -163,6 +175,7 @@ generatorHandler({
       typePrefix: "",
       typeSuffix: "",
       headerComment: "This file was auto-generated by prisma-generator-typescript-interfaces",
+      definitionType: "interface",
       enumType: "stringUnion",
       dateType: "Date",
       bigIntType: "bigint",

diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "prisma-generator-typescript-interfaces",
-  "version": "1.2.0",
+  "version": "1.3.0",
   "description": "Generate zero-dependency Typescript interfaces from Prisma schema",
   "author": "Morgan Zolob",
   "license": "MIT",

diff --git a/tests/options-behavior/expected/typeDefinitions.ts b/tests/options-behavior/expected/typeDefinitions.ts
@@ -0,0 +1,67 @@
+// This file was auto-generated by prisma-generator-typescript-interfaces
+
+export type Gender = "Male" | "Female" | "Other";
+
+export type DataTest = "Apple" | "Banana" | "Orange" | "Pear";
+
+export type Person = {
+  id: number;
+  name: string;
+  age: number;
+  email: string | null;
+  gender: Gender;
+  addressId: number;
+  address?: Address;
+  friends?: Person[];
+  friendsOf?: Person[];
+  data?: Data | null;
+};
+
+export type Address = {
+  id: number;
+  streetNumber: number;
+  streetName: string;
+  city: string;
+  isBilling: boolean;
+  people?: Person[];
+};
+
+export type Data = {
+  id: string;
+  stringField: string;
+  booleanField: boolean;
+  intField: number;
+  bigIntField: bigint;
+  floatField: number;
+  decimalField: Decimal;
+  dateField: Date;
+  jsonField: JsonValue;
+  bytesField: Buffer;
+  enumField: DataTest;
+  optionalStringField: string | null;
+  optionalBooleanField: boolean | null;
+  optionalIntField: number | null;
+  optionalBigIntField: bigint | null;
+  optionalFloatField: number | null;
+  optionalDecimalField: Decimal | null;
+  optionalDateField: Date | null;
+  optionalJsonField: JsonValue | null;
+  optionalBytesField: Buffer | null;
+  optionalEnumField: DataTest | null;
+  stringArrayField: string[];
+  booleanArrayField: boolean[];
+  intArrayField: number[];
+  bigIntArrayField: bigint[];
+  floatArrayField: number[];
+  decimalArrayField: Decimal[];
+  dateArrayField: Date[];
+  jsonArrayField: JsonValue[];
+  bytesArrayField: Buffer[];
+  enumArrayField: DataTest[];
+  personId: number;
+  person?: Person;
+};
+
+type Decimal = { valueOf(): string };
+
+type JsonValue = string | number | boolean | { [key in string]?: JsonValue } | Array<JsonValue> | null;
diff --git a/tests/options-behavior/schema.prisma b/tests/options-behavior/schema.prisma
@@ -90,6 +90,12 @@ generator enumTypeSuffixPrefix {
   enumSuffix = "Enum"
 }
 
+generator typeDefinitions {
+  provider       = "node --loader ts-node/esm generator.ts"
+  output         = "typeDefinitions.ts"
+  definitionType = "type"
+}
+
 // ========================
 // Prisma Schema
 // ========================

diff --git a/tests/validation-errors/expected-error.txt b/tests/validation-errors/expected-error.txt
@@ -1,4 +1,5 @@
 Error:
+Invalid definitionType: bad
 Invalid enumType: incorrect
 Invalid dateType: wrong
 Invalid bigIntType: values

diff --git a/tests/validation-errors/schema.prisma b/tests/validation-errors/schema.prisma
@@ -3,13 +3,13 @@
 // ========================
 
 generator typescriptInterfaces {
-  provider    = "node --loader ts-node/esm generator.ts"
-  enumType    = "incorrect"
-  dateType    = "wrong"
-  bigIntType  = "values"
-  decimalType = "go"
-  bytesType   = "here"
-  prettier    = "bad"
+  provider       = "node --loader ts-node/esm generator.ts"
+  definitionType = "bad"
+  enumType       = "incorrect"
+  dateType       = "wrong"
+  bigIntType     = "values"
+  decimalType    = "go"
+  bytesType      = "here"
 }
 
 // ========================