feat(primitives): implement positiveInt type

packages/primitives/src/index.ts

@@ -13,6 +13,7 @@ import { InstantType, instant } from "./instant";
 import { IntegerType, integer } from "./integer";
 import { MarkdownType, markdown } from "./markdown";
 import { OIDType, oid } from "./oid";
+import { PositiveIntegerType, positiveInt } from "./positiveInt";
 import { StringType, string } from "./string";
 import { TimeType, time } from "./time";
 import { UnsignedIntegerType, unsignedInt } from "./unsignedInt";
@@ -42,6 +43,8 @@ export {
   MarkdownType,
   oid,
   OIDType,
+  positiveInt,
+  PositiveIntegerType,
   string,
   StringType,
   time,

packages/primitives/src/positiveInt.ts

@@ -0,0 +1,19 @@
+/**
+ * Positive Integer FHIR Primitive Runtime Type
+ */
+
+import { Type, success, failure, identity } from "io-ts";
+
+export class PositiveIntegerType extends Type<number> {
+  readonly _tag: "PositiveIntegerType" = "PositiveIntegerType";
+  constructor() {
+    super(
+      "positiveInt",
+      (m): m is number => typeof m === "number" && Number.isInteger(m) && m > 0,
+      (m, c) => (this.is(m) ? success(m) : failure(m, c)),
+      identity
+    );
+  }
+}
+
+export const positiveInt = new PositiveIntegerType();

packages/primitives/test/positiveInt.test.ts

@@ -0,0 +1,45 @@
+/**
+ * Tests for Postive Integer Runtime Type
+ */
+
+import { positiveInt } from "../src";
+import { assertSuccess, assertFailure, assertStrictEqual } from "./helpers";
+
+describe("PositiveIntegerType", () => {
+  it("should succeed validating a valid value", () => {
+    const T = positiveInt;
+    assertSuccess(T.decode(2));
+  });
+
+  it("should return the same reference if validation succeeded and nothing changed", () => {
+    const T = positiveInt;
+    const value = 2;
+    assertStrictEqual(T.decode(value), value);
+  });
+
+  it("should fail validating a float", () => {
+    const T = positiveInt;
+    assertFailure(T.decode(1.1), [
+      "Invalid value 1.1 supplied to : positiveInt"
+    ]);
+  });
+
+  it("should fail validating a negative number", () => {
+    const T = positiveInt;
+    assertFailure(T.decode(-2), ["Invalid value -2 supplied to : positiveInt"]);
+  });
+
+  it("should fail validating 0", () => {
+    const T = positiveInt;
+    assertFailure(T.decode(0), ["Invalid value 0 supplied to : positiveInt"]);
+  });
+
+  it("should type guard", () => {
+    const T = positiveInt;
+    expect(T.is(2)).toEqual(true);
+    expect(T.is(0)).toEqual(false);
+    expect(T.is(1.1)).toEqual(false);
+    expect(T.is(-2)).toEqual(false);
+    expect(T.is(undefined)).toEqual(false);
+  });
+});