feat: add scalars config option for custom GraphQL [scalar -> casual] mappings (#21)

Some apps use custom scalar for date-related stuff. This caused issues with the way `graphql-codegen-typescript-mock-data` handles autogenerated data, since a "random string" (the current  default), may not always be what you need.

This PR allows you to define mapping from your custom scalars to a casual embedded generator, allowing you to specify exactly how your scalar's autogenerated value will be populated

Closes #20 

Co-authored-by: Corentin Ardeois <[email protected]>

Author: 3nvi

README.md

@@ -31,6 +31,12 @@ Changes the case of the enums. Accepts `upper-case#upperCase`, `pascal-case#pasc
 
 Changes the case of the enums. Accepts `upper-case#upperCase`, `pascal-case#pascalCase` or `keep`
 
+### scalars (`{ [Scalar: string]: keyof Casual.Casual | Casual.functions }`, defaultValue: `undefined`)
+
+Allows you to define mappings for your custom scalars. Allows you to map any GraphQL Scalar to a
+ [casual](https://github.com/boo1ean/casual#embedded-generators) embedded generator (string or
+ function key)
+
 ## Example of usage
 
 **codegen.yml**
@@ -48,13 +54,17 @@ generates:
           typesFile: '../generated-types.ts'
           enumValues: upper-case#upperCase
           typenames: keep
+          scalars:
+            AWSTimestamp: unix_time # gets translated to casual.unix_time
 ```
 
 ## Example or generated code
 
 Given the following schema:
 
 ```graphql
+scalar AWSTimestamp
+
 type Avatar {
   id: ID!
   url: String!
@@ -65,6 +75,7 @@ type User {
   login: String!
   avatar: Avatar
   status: Status!
+  updatedAt: AWSTimestamp
 }
 
 type Query {
@@ -111,6 +122,7 @@ export const aUser = (overrides?: Partial<User>): User => {
     login: overrides && overrides.hasOwnProperty('login') ? overrides.login! : 'libero',
     avatar: overrides && overrides.hasOwnProperty('avatar') ? overrides.avatar! : anAvatar(),
     status: overrides && overrides.hasOwnProperty('status') ? overrides.status! : Status.Online,
+    updatedAt: overrides && overrides.hasOwnProperty('updatedAt') ? overrides.updatedAt! : 1458071232,
   };
 };
 ```

src/index.ts

@@ -64,6 +64,7 @@ const getNamedType = (
     enumValuesConvention: NamingConvention,
     prefix?: string,
     namedType?: NamedTypeNode,
+    customScalars?: ScalarMap,
 ): string | number | boolean => {
     if (!namedType) {
         return '';
@@ -105,10 +106,26 @@ const getNamedType = (
                             prefix,
                             foundType.types && foundType.types[0],
                         );
-                    case 'scalar':
-                        // it's a scalar, let's use a string as a value.
-                        // This could be improved with a custom scalar definition in the config
-                        return `'${casual.word}'`;
+                    case 'scalar': {
+                        // it's a scalar, let's use a string as a value if there is no custom
+                        // mapping for this particular scalar
+                        if (!customScalars || !customScalars[foundType.name]) {
+                            return `'${casual.word}'`;
+                        }
+
+                        // If there is a mapping to a `casual` type, then use it and make sure
+                        // to call it if it's a function
+                        const embeddedGenerator = casual[customScalars[foundType.name]];
+                        const value = typeof embeddedGenerator === 'function' ? embeddedGenerator() : embeddedGenerator;
+
+                        if (typeof value === 'string') {
+                            return `'${value}'`;
+                        }
+                        if (typeof value === 'object') {
+                            return `${JSON.stringify(value)}`;
+                        }
+                        return value;
+                    }
                     default:
                         throw `foundType is unknown: ${foundType.name}: ${foundType.type}`;
                 }
@@ -126,6 +143,7 @@ const generateMockValue = (
     enumValuesConvention: NamingConvention,
     prefix: string | undefined,
     currentType: TypeNode,
+    customScalars: ScalarMap,
 ): string | number | boolean => {
     switch (currentType.kind) {
         case 'NamedType':
@@ -137,6 +155,7 @@ const generateMockValue = (
                 enumValuesConvention,
                 prefix,
                 currentType as NamedTypeNode,
+                customScalars,
             );
         case 'NonNullType':
             return generateMockValue(
@@ -147,6 +166,7 @@ const generateMockValue = (
                 enumValuesConvention,
                 prefix,
                 currentType.type,
+                customScalars,
             );
         case 'ListType': {
             const value = generateMockValue(
@@ -157,6 +177,7 @@ const generateMockValue = (
                 enumValuesConvention,
                 prefix,
                 currentType.type,
+                customScalars,
             );
             return `[${value}]`;
         }
@@ -180,12 +201,15 @@ ${fields}
 };`;
 };
 
+type ScalarMap = { [name: string]: keyof (Casual.Casual | Casual.functions) };
+
 export interface TypescriptMocksPluginConfig {
     typesFile?: string;
     enumValues?: NamingConvention;
     typenames?: NamingConvention;
     addTypename?: boolean;
     prefix?: string;
+    scalars?: ScalarMap;
 }
 
 interface TypeItem {
@@ -243,6 +267,7 @@ export const plugin: PluginFunction<TypescriptMocksPluginConfig> = (schema, docu
                         enumValuesConvention,
                         config.prefix,
                         node.type,
+                        config.scalars,
                     );
 
                     return `        ${fieldName}: overrides && overrides.hasOwnProperty('${fieldName}') ? overrides.${fieldName}! : ${value},`;
@@ -266,6 +291,7 @@ export const plugin: PluginFunction<TypescriptMocksPluginConfig> = (schema, docu
                                       enumValuesConvention,
                                       config.prefix,
                                       field.type,
+                                      config.scalars,
                                   );
 
                                   return `        ${field.name.value}: overrides && overrides.hasOwnProperty('${field.name.value}') ? overrides.${field.name.value}! : ${value},`;

tests/__snapshots__/typescript-mock-data.spec.ts.snap

@@ -37,6 +37,80 @@ export const mockUser = (overrides?: Partial<User>): User => {
 "
 `;
 
+exports[`should correctly generate the \`casual\` data for a non-string scalar mapping 1`] = `
+"
+export const anAbcType = (overrides?: Partial<AbcType>): AbcType => {
+    return {
+        abc: overrides && overrides.hasOwnProperty('abc') ? overrides.abc! : 'sit',
+    };
+};
+
+export const anAvatar = (overrides?: Partial<Avatar>): Avatar => {
+    return {
+        id: overrides && overrides.hasOwnProperty('id') ? overrides.id! : '0550ff93-dd31-49b4-8c38-ff1cb68bdc38',
+        url: overrides && overrides.hasOwnProperty('url') ? overrides.url! : 'aliquid',
+    };
+};
+
+export const aUpdateUserInput = (overrides?: Partial<UpdateUserInput>): UpdateUserInput => {
+    return {
+        id: overrides && overrides.hasOwnProperty('id') ? overrides.id! : '1d6a9360-c92b-4660-8e5f-04155047bddc',
+        login: overrides && overrides.hasOwnProperty('login') ? overrides.login! : 'qui',
+        avatar: overrides && overrides.hasOwnProperty('avatar') ? overrides.avatar! : anAvatar(),
+    };
+};
+
+export const aUser = (overrides?: Partial<User>): User => {
+    return {
+        id: overrides && overrides.hasOwnProperty('id') ? overrides.id! : 'a5756f00-41a6-422a-8a7d-d13ee6a63750',
+        creationDate: overrides && overrides.hasOwnProperty('creationDate') ? overrides.creationDate! : '1970-01-09T16:33:21.532Z',
+        login: overrides && overrides.hasOwnProperty('login') ? overrides.login! : 'libero',
+        avatar: overrides && overrides.hasOwnProperty('avatar') ? overrides.avatar! : anAvatar(),
+        status: overrides && overrides.hasOwnProperty('status') ? overrides.status! : Status.Online,
+        customStatus: overrides && overrides.hasOwnProperty('customStatus') ? overrides.customStatus! : AbcStatus.HasXyzStatus,
+        scalarValue: overrides && overrides.hasOwnProperty('scalarValue') ? overrides.scalarValue! : [41,98,185],
+    };
+};
+"
+`;
+
+exports[`should correctly generate the \`casual\` data for a scalar mapping of type string 1`] = `
+"
+export const anAbcType = (overrides?: Partial<AbcType>): AbcType => {
+    return {
+        abc: overrides && overrides.hasOwnProperty('abc') ? overrides.abc! : 'sit',
+    };
+};
+
+export const anAvatar = (overrides?: Partial<Avatar>): Avatar => {
+    return {
+        id: overrides && overrides.hasOwnProperty('id') ? overrides.id! : '0550ff93-dd31-49b4-8c38-ff1cb68bdc38',
+        url: overrides && overrides.hasOwnProperty('url') ? overrides.url! : 'aliquid',
+    };
+};
+
+export const aUpdateUserInput = (overrides?: Partial<UpdateUserInput>): UpdateUserInput => {
+    return {
+        id: overrides && overrides.hasOwnProperty('id') ? overrides.id! : '1d6a9360-c92b-4660-8e5f-04155047bddc',
+        login: overrides && overrides.hasOwnProperty('login') ? overrides.login! : 'qui',
+        avatar: overrides && overrides.hasOwnProperty('avatar') ? overrides.avatar! : anAvatar(),
+    };
+};
+
+export const aUser = (overrides?: Partial<User>): User => {
+    return {
+        id: overrides && overrides.hasOwnProperty('id') ? overrides.id! : 'a5756f00-41a6-422a-8a7d-d13ee6a63750',
+        creationDate: overrides && overrides.hasOwnProperty('creationDate') ? overrides.creationDate! : '1970-01-09T16:33:21.532Z',
+        login: overrides && overrides.hasOwnProperty('login') ? overrides.login! : 'libero',
+        avatar: overrides && overrides.hasOwnProperty('avatar') ? overrides.avatar! : anAvatar(),
+        status: overrides && overrides.hasOwnProperty('status') ? overrides.status! : Status.Online,
+        customStatus: overrides && overrides.hasOwnProperty('customStatus') ? overrides.customStatus! : AbcStatus.HasXyzStatus,
+        scalarValue: overrides && overrides.hasOwnProperty('scalarValue') ? overrides.scalarValue! : '[email protected]',
+    };
+};
+"
+`;
+
 exports[`should generate mock data functions 1`] = `
 "
 export const anAbcType = (overrides?: Partial<AbcType>): AbcType => {

tests/typescript-mock-data.spec.ts

@@ -177,3 +177,19 @@ it('should add custom prefix if the `prefix` config option is specified', async
     expect(result).not.toMatch(/const aUser/);
     expect(result).toMatchSnapshot();
 });
+
+it('should correctly generate the `casual` data for a scalar mapping of type string', async () => {
+    const result = await plugin(testSchema, [], { scalars: { AnyObject: 'email' } });
+
+    expect(result).toBeDefined();
+    expect(result).toContain('[email protected]');
+    expect(result).toMatchSnapshot();
+});
+
+it('should correctly generate the `casual` data for a non-string scalar mapping', async () => {
+    const result = await plugin(testSchema, [], { scalars: { AnyObject: 'rgb_array' } });
+
+    expect(result).toBeDefined();
+    expect(result).toContain(JSON.stringify([41, 98, 185]));
+    expect(result).toMatchSnapshot();
+});