Require workouts to have a name

src/parser/parser.test.ts

@@ -1,14 +1,13 @@
 import { parse } from ".";
 
 describe("Parser", () => {
-  it("parses empty workout file", () => {
-    expect(parse("")).toMatchInlineSnapshot(`
-      Object {
-        "author": "",
-        "description": "",
-        "intervals": Array [],
-        "name": "",
-      }
-    `);
+  it("throws error for empty file", () => {
+    expect(() => parse("")).toThrowErrorMatchingInlineSnapshot(
+      `"Workout is missing a name. Use \`Name:\` to declare one."`
+    );
+
+    expect(() => parse("  \n  \n \t")).toThrowErrorMatchingInlineSnapshot(
+      `"Workout is missing a name. Use \`Name:\` to declare one."`
+    );
   });
 });

src/parser/parser.ts

@@ -107,8 +107,13 @@ const parseIntervals = (tokens: Token[]): Interval[] => {
 
 export const parseTokens = (tokens: Token[]): Workout => {
   const [header, intervalTokens] = parseHeader(tokens);
+
+  if (header.name === undefined) {
+    throw new Error("Workout is missing a name. Use `Name:` to declare one.");
+  }
+
   return {
-    name: header.name || "",
+    name: header.name,
     author: header.author || "",
     description: header.description || "",
     intervals: parseIntervals(intervalTokens),