adds flatten function and tests

src/types/__tests__/flatten.test.ts

@@ -0,0 +1,19 @@
+import * as E from "fp-ts/Either";
+import { FlattenMapping } from "../flatten";
+
+describe("FlattenMapping", () => {
+  it("should decode if config is a valid FlattenMapping", () => {
+    const validData = {
+      mapper: "FLATTEN"
+    };
+    const result = FlattenMapping.decode(validData);
+    expect(E.isRight(result)).toBeTruthy();
+  });
+  it("should not validate if config is not a valid input", () => {
+    const invalidData = {
+      mapper: "INVALID_MAPPER"
+    };
+    const result = FlattenMapping.decode(invalidData);
+    expect(E.isRight(result)).toBeFalsy();
+  });
+});

src/types/__tests__/singleInput.test.ts

@@ -106,6 +106,18 @@ const invalidConvertFormatMapping = {
   output: "invalid output string"
 };
 
+const flattenMapping = {
+  type: "SINGLE_INPUT",
+  inputFieldName: "foo",
+  mapper: "FLATTEN"
+};
+
+const invalidFlattenMapping = {
+  type: "SINGLE_INPUT",
+  inputFieldName: "foo",
+  mapper: "INVALID"
+};
+
 describe("SingleInputMapping", () => {
   it("should decode a correct numberCaseMapping type properly", () => {
     const res = SingleInputMapping.decode(numberCaseMapping);
@@ -163,4 +175,12 @@ describe("SingleInputMapping", () => {
     const res = SingleInputMapping.decode(invalidConvertFormatMapping);
     expect(E.isLeft(res)).toBeTruthy();
   });
+  it("should decode a correct flattenMapping type properly", () => {
+    const res = SingleInputMapping.decode(flattenMapping);
+    expect(E.isRight(res)).toBeTruthy();
+  });
+  it("should not decode an invalid flattenMapping type properly", () => {
+    const res = SingleInputMapping.decode(invalidFlattenMapping);
+    expect(E.isLeft(res)).toBeTruthy();
+  });
 });

src/types/flatten.ts

@@ -0,0 +1,7 @@
+import * as t from "io-ts";
+
+export const FlattenMapping = t.type({
+  mapper: t.literal("FLATTEN")
+});
+
+type FlattenMapping = t.TypeOf<typeof FlattenMapping>;

src/types/singleInput.ts

@@ -3,6 +3,7 @@ import * as t from "io-ts";
 import { BooleanMapping } from "./boolean";
 import { SwitchCaseMapping } from "./case";
 import { DateMapping } from "./date";
+import { FlattenMapping } from "./flatten";
 import { NumberMapping } from "./number";
 import { RenameFieldMapping } from "./renameField";
 import { StringMapping } from "./string";
@@ -55,13 +56,19 @@ export const SingleInputDateMapping = t.intersection([
   DateMapping
 ]);
 
+export const SingleInputFlattenMapping = t.intersection([
+  SingleInputConfig,
+  FlattenMapping
+]);
+
 export const SingleInputMapping = t.union([
   SingleInputNumberMapping,
   SingleInputStringMapping,
   SingleInputBooleanMapping,
   SingleInputRenameFieldMapping,
   SingleInputSwitchCaseMapping,
-  SingleInputDateMapping
+  SingleInputDateMapping,
+  SingleInputFlattenMapping
 ]);
 
 export type SingleInputMapping = t.TypeOf<typeof SingleInputMapping>;