Handle named function types specially in matchModuloWhitespace (#214)

* repro for issue 213

* fix the bug

src/test/ts-checker.test.ts

@@ -516,6 +516,12 @@ describe('ts-checker', () => {
         matchModuloWhitespace('BoundingBox | undefined', 'const box: BoundingBox | undefined'),
       ).toBe(false);
     });
+
+    it('should normalize whitespace in function types', () => {
+      const actual = `function fetchANumber(input: RequestInfo | URL, init?: RequestInit | undefined): Promise<number>`;
+      const expected = `function fetchANumber( input: RequestInfo | URL, init?: RequestInit | undefined ): Promise<number>`;
+      expect(matchModuloWhitespace(actual, expected)).toBe(true);
+    });
   });
 
   describe('sortUnions', () => {

src/ts-checker.ts

@@ -389,18 +389,28 @@ export function matchModuloWhitespace(actual: string, expected: string): boolean
   // TODO: it's much easier to normalize actual based on the displayParts
   //       This isn't 100% correct if a type has a space in it, e.g. type T = "string literal"
   const normalize = (input: string) => {
-    const parts = input.split(/[:=]/, 2);
-    if (parts.length !== 2) {
-      // this might be a typo, e.g. missing the ":" or "=" in a type assertion.
-      return input;
+    const isFunction = !!input.match(/^ *function /);
+
+    let name: string;
+    let type: string;
+    if (!isFunction) {
+      const parts = input.split(/[:=]/, 2);
+      if (parts.length !== 2) {
+        // this might be a typo, e.g. missing the ":" or "=" in a type assertion.
+        return input;
+      }
+      [name, type] = parts;
+    } else {
+      name = 'n/a';
+      type = input;
     }
-    const [name, type] = parts;
+
     const normType = sortUnions(type)
       .replace(/[\n\r ]+/g, ' ')
       .replace(/\( */g, '(')
       .replace(/ *\)/, ')')
       .trim();
-    return `${name}: ${normType}`;
+    return isFunction ? normType : `${name}: ${normType}`;
   };
   const normActual = normalize(actual);
   const normExpected = normalize(expected);