add All function

itlib/each.go

@@ -128,3 +128,9 @@ func Any[T any](it itkit.Iterator[T], fn EachFn[T]) (ok bool) {
 	Each(it, func(x T) bool { ok = fn(x); return ok })
 	return
 }
+
+// All tests if all items in the iterator matches a predicate.
+func All[T any](it itkit.Iterator[T], fn EachFn[T]) (ok bool) {
+	Each(it, func(x T) bool { ok = fn(x); return !ok })
+	return
+}

itlib/each_test.go

@@ -224,3 +224,24 @@ func TestAny(t *testing.T) {
 		})
 	}
 }
+
+func TestAll(t *testing.T) {
+	type testCase[T any] struct {
+		name   string
+		args   []bool
+		wantOk bool
+	}
+	tt := []testCase[bool]{
+		{"false", []bool{false, false, false}, false},
+		{"false2", []bool{false, false, true}, false},
+		{"true", []bool{true, true, true}, true},
+	}
+	for _, tt := range tt {
+		t.Run(tt.name, func(t *testing.T) {
+			got := itlib.All(sliceit.In(tt.args), func(item bool) bool {
+				return item
+			})
+			assertpkg.Equal(t, tt.wantOk, got)
+		})
+	}
+}