fix: inference of optional properties (#28)

javascript/src/rpc.spec.ts

@@ -758,18 +758,52 @@ describe('RetoolRPC', () => {
       arguments: {},
       implementation: async () => {
         return 1
-      }
+      },
     })
 
     type ExpectedImplementation = (args: TransformedArguments<Arguments>, context: RetoolContext) => Promise<number>
     expectTypeOf(fn).toEqualTypeOf<ExpectedImplementation>()
-
 
-    const result = await fn({}, context);
+    const result = await fn({}, context)
     expect(result).toEqual(1)
     expectTypeOf(result).toEqualTypeOf(1)
   })
 
+  test('infers non-required properties as optional', async () => {
+    const fn = rpcAgent.register({
+      name: 'test',
+      arguments: {
+        explicitRequired: {
+          type: 'number',
+          required: true,
+        },
+        explicitOptional: {
+          type: 'number',
+          required: false,
+        },
+        implicitOptional: {
+          type: 'number',
+        },
+      },
+      implementation: async (args) => {
+        expectTypeOf(args.explicitRequired).toEqualTypeOf<number>()
+
+        expectTypeOf(args.explicitOptional).toEqualTypeOf<number | undefined>()
+        expectTypeOf(args.implicitOptional).toEqualTypeOf<number | undefined>()
+
+        return args
+      },
+    })
+
+    const result = await fn(
+      {
+        explicitRequired: 1,
+      },
+      context,
+    )
+
+    expectTypeOf(result.explicitOptional).toEqualTypeOf<number | undefined>()
+  })
 })
 
 describe('RetoolRPCVersion', () => {

javascript/src/rpc.ts

@@ -89,13 +89,15 @@ export class RetoolRPC {
   /**
    * Registers a Retool function with the specified function definition.
    */
-  register<TArgs extends Arguments, TReturn>(spec: RegisterFunctionSpec<TArgs, TReturn>): RegisterFunctionSpec<TArgs, TReturn>['implementation'] {
+  register<TArgs extends Arguments, TReturn>(
+    spec: RegisterFunctionSpec<TArgs, TReturn>,
+  ): RegisterFunctionSpec<TArgs, TReturn>['implementation'] {
     this._functions[spec.name] = {
       arguments: spec.arguments,
       permissions: spec.permissions,
-      implementation: spec.implementation,
+      implementation: spec.implementation as RegisterFunctionSpec<any, any>['implementation'],
     }
-    return spec.implementation;
+    return spec.implementation
   }
 
   /**

javascript/src/types.ts

@@ -36,11 +36,17 @@ export type ArgumentType = 'string' | 'boolean' | 'number' | 'dict' | 'json'
 export type Argument = {
   /** The type of the argument. */
   type: ArgumentType
-  /** Specifies whether the argument is expected to be an array. */
+  /**
+   * Specifies whether the argument is expected to be an array.
+   * @default false
+   */
   array?: boolean
   /** The description of the argument. */
   description?: string
-  /** Specifies whether the argument is required. */
+  /**
+   * Specifies whether the argument is required.
+   * @default false
+   */
   required?: boolean
 }
 
@@ -68,10 +74,18 @@ export type TransformedArgument<TArg extends Argument> = TArg['array'] extends t
   ? Array<ArgumentTypeMap<TArg>>
   : ArgumentTypeMap<TArg>
 
+type PartialBy<T, K extends keyof T> = Omit<T, K> & Partial<Pick<T, K>>
+type GetOptionalArgs<TArgs extends Arguments> = {
+  [TArg in keyof TArgs]: TArgs[TArg]['required'] extends true ? never : TArg
+}[keyof TArgs]
+
 /** Represents a map of argument names to argument types. */
-export type TransformedArguments<TArgs extends Arguments> = {
-  [TArg in keyof TArgs]: TransformedArgument<TArgs[TArg]>
-}
+export type TransformedArguments<TArgs extends Arguments> = PartialBy<
+  {
+    [TArg in keyof TArgs]: TransformedArgument<TArgs[TArg]>
+  },
+  GetOptionalArgs<TArgs>
+>
 
 /** Represents the specification for registering a Retool function. */
 export type RegisterFunctionSpec<TArgs extends Arguments, TReturn> = {

javascript/tsconfig.json

@@ -11,13 +11,13 @@
     /* Additional Checks */
     "skipLibCheck": true,
     "esModuleInterop": true,
-    "allowSyntheticDefaultImports": true,
+    "allowSyntheticDefaultImports": true
   },
   "ts-node": {
     // these options are overrides used only by ts-node
     // same as the --compilerOptions flag and the TS_NODE_COMPILER_OPTIONS environment variable
     "compilerOptions": {
       "module": "commonjs"
     }
-  },
+  }
 }