feat(primitives): implement canonical type

packages/primitives/src/canonical.ts

@@ -0,0 +1,20 @@
+/**
+ * Canonical URL FHIR Primitive Runtime Type
+ */
+
+import { uri } from "./uri";
+import { Type, success, failure, identity } from "io-ts";
+
+export class CanonicalType extends Type<string> {
+  readonly _tag: "CanonicalType" = "CanonicalType";
+  constructor() {
+    super(
+      "canonical",
+      uri.is,
+      (m, c) => (this.is(m) ? success(m) : failure(m, c)),
+      identity
+    );
+  }
+}
+
+export const canonical = new CanonicalType();

packages/primitives/src/index.ts

@@ -3,6 +3,7 @@
  */
 
 import { BooleanType, boolean } from "./boolean";
+import { CanonicalType, canonical } from "./canonical";
 import { DecimalType, decimal } from "./decimal";
 import { IntegerType, integer } from "./integer";
 import { StringType, string } from "./string";
@@ -12,6 +13,8 @@ import { URLType, url } from "./url";
 export {
   boolean,
   BooleanType,
+  canonical,
+  CanonicalType,
   decimal,
   DecimalType,
   integer,

packages/primitives/test/canonical.test.ts

@@ -0,0 +1,32 @@
+/**
+ * Tests for Canonical URL Runtime Type
+ */
+
+import { assertSuccess, assertFailure, assertStrictEqual } from "./helpers";
+import { canonical } from "../src";
+
+describe("CanonicalType", () => {
+  it("should succeed validating a valid value", () => {
+    const T = canonical;
+    const input = "http://snomed.info/sct";
+    assertSuccess(T.decode(input));
+  });
+
+  it("should return the same reference if validation succeeded and nothing changed", () => {
+    const T = canonical;
+    const value = "http://snomed.info/sct";
+    assertStrictEqual(T.decode(value), value);
+  });
+
+  it("should fail validating an invalid value", () => {
+    const T = canonical;
+    assertFailure(T.decode(2), ["Invalid value 2 supplied to : canonical"]);
+  });
+
+  it("should type guard", () => {
+    const T = canonical;
+    expect(T.is("http://snomed.info/sct")).toEqual(true);
+    expect(T.is(2)).toEqual(false);
+    expect(T.is(undefined)).toEqual(false);
+  });
+});