fix(types): fix ExtractedValue type (#4334)

cheeriojs · Feb 19, 2025 · 6e31241 · 6e31241
1 parent d6bd0cb
commit 6e31241
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Showing 2 changed files with 70 additions and 8 deletions.
diff --git a/src/api/extract.spec.ts b/src/api/extract.spec.ts
@@ -152,6 +152,28 @@ describe('$.extract', () => {
     ).toStrictEqual({ red: 'red=Four' });
   });
 
+  it('should correctly type check custom extraction functions returning non-string values', () => {
+    const $ = load(fixtures.eleven);
+    const $root = $.root();
+
+    expectTypeOf(
+      $root.extract({
+        red: {
+          selector: '.red',
+          value: (el) => $(el).text().length,
+        },
+      }),
+    ).toEqualTypeOf<{ red: number | undefined }>();
+    expect(
+      $root.extract({
+        red: {
+          selector: '.red',
+          value: (el) => $(el).text().length,
+        },
+      }),
+    ).toStrictEqual({ red: 4 });
+  });
+
   it('should extract multiple values using custom extraction functions', () => {
     const $ = load(fixtures.eleven);
     const $root = $.root();
@@ -215,6 +237,44 @@ describe('$.extract', () => {
     });
   });
 
+  it('should correctly type check nested objects returning non-string values', () => {
+    const $ = load(fixtures.eleven);
+    const $root = $.root();
+
+    expectTypeOf(
+      $root.extract({
+        section: {
+          selector: 'ul:nth(1)',
+          value: {
+            red: {
+              selector: '.red',
+              value: (el) => $(el).text().length,
+            },
+          },
+        },
+      }),
+    ).toEqualTypeOf<{
+      section: { red: number | undefined } | undefined;
+    }>();
+    expect(
+      $root.extract({
+        section: {
+          selector: 'ul:nth(1)',
+          value: {
+            red: {
+              selector: '.red',
+              value: (el) => $(el).text().length,
+            },
+          },
+        },
+      }),
+    ).toStrictEqual({
+      section: {
+        red: 4,
+      },
+    });
+  });
+
   it('should handle missing href properties without errors (#4239)', () => {
     const $ = load(fixtures.eleven);
     expect<{ links: string[] }>(

diff --git a/src/api/extract.ts b/src/api/extract.ts
@@ -18,22 +18,24 @@ type ExtractValue = string | ExtractDescriptor | [string | ExtractDescriptor];
 
 export type ExtractMap = Record<string, ExtractValue>;
 
-type ExtractedValue<V extends ExtractValue, M extends ExtractMap> = V extends [
+type ExtractedValue<V extends ExtractValue> = V extends [
   string | ExtractDescriptor,
 ]
-  ? NonNullable<ExtractedValue<V[0], M>>[]
+  ? NonNullable<ExtractedValue<V[0]>>[]
   : V extends string
     ? string | undefined
     : V extends ExtractDescriptor
-      ? V['value'] extends ExtractMap
-        ? ExtractedMap<V['value']> | undefined
-        : V['value'] extends ExtractDescriptorFn
-          ? ReturnType<V['value']> | undefined
-          : ReturnType<typeof prop> | undefined
+      ? V['value'] extends infer U
+        ? U extends ExtractMap
+          ? ExtractedMap<U> | undefined
+          : U extends ExtractDescriptorFn
+            ? ReturnType<U> | undefined
+            : ReturnType<typeof prop> | undefined
+        : never
       : never;
 
 export type ExtractedMap<M extends ExtractMap> = {
-  [key in keyof M]: ExtractedValue<M[key], M>;
+  [key in keyof M]: ExtractedValue<M[key]>;
 };
 
 function getExtractDescr(