fix determining if the source is cacheable

biome.json

@@ -46,7 +46,8 @@
         "noDynamicNamespaceImportAccess": "off"
       },
       "suspicious": {
-        "noAssignInExpressions": "off"
+        "noAssignInExpressions": "off",
+        "useIterableCallbackReturn": "off"
       }
     }
   }

lib/caching/index.js

@@ -13,3 +13,21 @@ export function getStrategy(caching, object) {
   }
   return caching.evaluate(object);
 }
+
+function getValues(caching, values = []) {
+  if (typeof caching === 'string') {
+    values.push(caching);
+    return values;
+  }
+  if (Array.isArray(caching)) {
+    caching.forEach(item => getValues(item, values));
+  }
+  return values;
+}
+
+export function isCacheable(caching) {
+  if (!caching) {
+    return;
+  }
+  return getValues(caching).some(key => key.startsWith('cache-'));
+}

lib/map-style.js

@@ -1,3 +1,4 @@
+import { isCacheable } from './caching/index.js';
 import loadGlyphs from './glyphs.js';
 import { init as initLayers, reset as resetLayers } from './layers.js';
 import loader from './loader.js';
@@ -114,14 +115,3 @@ function cacheableOnly(style) {
 
   return cached;
 }
-
-function isCacheable(caching) {
-  if (!caching) {
-    return;
-  }
-  const keys = Object.keys(caching);
-  if (caching.default) {
-    keys.push(caching.default);
-  }
-  return keys.some(key => key.startsWith('cache-'));
-}

test/caching.js

@@ -1,6 +1,6 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
-import { getStrategy, initCaching } from '../lib/caching/index.js';
+import { getStrategy, initCaching, isCacheable } from '../lib/caching/index.js';
 
 test('caching default', () => {
   const caching = initCaching('do-nothing');
@@ -72,3 +72,29 @@ test('caching multiple fields', () => {
   strategy = getStrategy(caching, {});
   assert.equal(strategy, 'do-nothing');
 });
+
+test('isCacheable', () => {
+  assert.equal(isCacheable('do-nothing'), false);
+  assert.equal(
+    isCacheable([
+      'case',
+      ['all', ['to-boolean', ['global-state', 'field1']], ['to-boolean', ['global-state', 'field2']]],
+      'network-only',
+      'do-nothing'
+    ]),
+    false
+  );
+
+  assert.equal(isCacheable('cache-only'), true);
+  assert.equal(
+    isCacheable([
+      'case',
+      ['to-boolean', ['global-state', 'field1']],
+      'network-only',
+      ['to-boolean', ['global-state', 'field2']],
+      'cache-only',
+      'do-nothing'
+    ]),
+    true
+  );
+});