utils: Separate assertDefined and assertDefinedAndNotNull

packages/utils/src/assert.spec.ts

@@ -1,6 +1,55 @@
-import { assertDefinedAndNotNull } from "./assert";
+import { assertDefined, assertDefinedAndNotNull } from "./assert";
 
 describe("assert", () => {
+  describe("assertDefined", () => {
+    it("passes for simple values", () => {
+      {
+        const value: number | undefined = 123;
+        assertDefined(value);
+        expect(value).toEqual(123);
+      }
+      {
+        const value: string | undefined = "abc";
+        assertDefined(value);
+        expect(value).toEqual("abc");
+      }
+    });
+
+    it("passes for falsy values", () => {
+      {
+        const value: number | undefined = 0;
+        assertDefined(value);
+        expect(value).toEqual(0);
+      }
+      {
+        const value: string | undefined = "";
+        assertDefined(value);
+        expect(value).toEqual("");
+      }
+      {
+        const value: null | undefined = null;
+        assertDefined(value);
+        expect(value).toBeNull();
+      }
+    });
+
+    it("throws for undefined values", () => {
+      {
+        const value: number | undefined = undefined;
+        expect(() => assertDefined(value)).toThrowError("value is undefined");
+      }
+      {
+        let value: string | undefined;
+        expect(() => assertDefined(value)).toThrowError("value is undefined");
+      }
+    });
+
+    it("throws with custom message", () => {
+      const value: number | undefined = undefined;
+      expect(() => assertDefined(value, "Bug in the data source")).toThrowError("Bug in the data source");
+    });
+  });
+
   describe("assertDefinedAndNotNull", () => {
     it("passes for simple values", () => {
       {

packages/utils/src/assert.ts

@@ -5,6 +5,12 @@ export function assert(condition: any, msg?: string): asserts condition {
   }
 }
 
+export function assertDefined<T>(value: T | undefined, msg?: string): asserts value is T {
+  if (value === undefined) {
+    throw new Error(msg ?? "value is undefined");
+  }
+}
+
 export function assertDefinedAndNotNull<T>(value: T | undefined | null, msg?: string): asserts value is T {
   if (value === undefined || value === null) {
     throw new Error(msg ?? "value is undefined or null");

packages/utils/src/index.ts

@@ -1,4 +1,4 @@
 export { arrayContentEquals } from "./arrays";
-export { assert, assertDefinedAndNotNull } from "./assert";
+export { assert, assertDefined, assertDefinedAndNotNull } from "./assert";
 export { sleep } from "./sleep";
 export { isNonNullObject, isUint8Array } from "./typechecks";

packages/utils/types/assert.d.ts

@@ -1,4 +1,5 @@
 export declare function assert(condition: any, msg?: string): asserts condition;
+export declare function assertDefined<T>(value: T | undefined, msg?: string): asserts value is T;
 export declare function assertDefinedAndNotNull<T>(
   value: T | undefined | null,
   msg?: string,

packages/utils/types/index.d.ts

@@ -1,4 +1,4 @@
 export { arrayContentEquals } from "./arrays";
-export { assert, assertDefinedAndNotNull } from "./assert";
+export { assert, assertDefined, assertDefinedAndNotNull } from "./assert";
 export { sleep } from "./sleep";
 export { isNonNullObject, isUint8Array } from "./typechecks";