diff --git a/src/formatter/__test__/case.test.ts b/src/formatter/__test__/case.test.ts
new file mode 100644
index 0000000..9c3d5c4
--- /dev/null
+++ b/src/formatter/__test__/case.test.ts
@@ -0,0 +1,21 @@
+import { switchCaseFormat } from "../case";
+
+describe("switchCaseFormat", () => {
+  const aFieldValue = "foo";
+  const switchCaseMapping = { bar: "foo", foo: "bar" };
+  const anotherSwitchCaseMapping = { 1: 2, 2: 1 };
+  it("should return correct mapping if fieldValue matches a case", () => {
+    const processor = switchCaseFormat(switchCaseMapping, "");
+    expect(processor(aFieldValue)).toEqual(switchCaseMapping[aFieldValue]);
+  });
+
+  it("should return correct mapping with fieldValue type narrowing matching a case", () => {
+    const processor = switchCaseFormat(anotherSwitchCaseMapping, 0);
+    expect(processor(1)).toEqual(anotherSwitchCaseMapping[1]);
+  });
+
+  it("should return default mapping if fieldValue deos not match a case", () => {
+    const processor = switchCaseFormat(switchCaseMapping, "");
+    expect(processor(1)).toEqual("");
+  });
+});
diff --git a/src/formatter/case.ts b/src/formatter/case.ts
new file mode 100644
index 0000000..3e81a90
--- /dev/null
+++ b/src/formatter/case.ts
@@ -0,0 +1,12 @@
+import { pipe } from "fp-ts/lib/function";
+import * as O from "fp-ts/lib/Option";
+
+export const switchCaseFormat = <T>(
+  cases: { readonly [key: string]: T },
+  defaultValue: T
+) => (field: unknown): T =>
+  pipe(
+    cases[`${field}`],
+    O.fromNullable,
+    O.getOrElse(() => defaultValue)
+  );