fix: wait for running items before end resolution

README.md

@@ -73,7 +73,7 @@ Multiple items (arrays) are merged. Muliple options (objects) are merged as well
 - `call`   
   Execute one or several items and return a promise with the resolved value. Unless the `fluent` option is `false`, it is also possible to chain additional functions.
 - `end(error|options)`   
-  Close the scheduler. No further items are allowed to register with `call`, or an error is thrown. It returns a promise that resolves once all previously scheduled items are resolved. When `end` is called and each is in paused state, all paused items are resolved with `undefined` or an error if any.    
+  Close the scheduler. No further items are allowed to register with `call`, or the returned promise is rejected. It returns a promise that resolves once all previously scheduled items resolve. When `end` is called and the scheduler is in paused state, all paused items are resolved with `undefined` or an error if any.    
   Available options:
   - `error`   
     Reject the returned promise and every registered item that is not yet executed with an error. All scheduled items not yet executed are resolved with an error. In `relax` mode, only the promise returned by `end` is rejected with an error.

lib/index.js

@@ -90,10 +90,20 @@ export default function () {
     running: 0,
     count: 0,
     stack: [],
+    stack_running: [],
+    close_item: undefined,
   };
   const internal = {
     pump: function () {
       detach(async function () {
+        if (state.closed && state.close_item && state.stack_running.length === 0) {
+          if (state.error && !options.relax) {
+            state.close_item.reject(state.error);
+          } else {
+            state.close_item.resolve();
+          }
+          return;
+        }
         if (!state.stack.length) {
           return;
         }
@@ -105,12 +115,9 @@ export default function () {
         }
         const item = state.stack.shift();
         if (item.type === "END") {
-          if (state.stack.length !== 0) console.error("EACH_INVALID_STATE");
-          if (state.error && !options.relax) {
-            item.reject(state.error);
-          } else {
-            item.resolve();
-          }
+          // Place the item on the side to ensure that running item are completed.
+          state.close_item = item;
+          internal.pump();
           return;
         } else if (item.type === "ERROR") {
           state.error = item.value;
@@ -129,10 +136,14 @@ export default function () {
             : typeof item.handler === "function"
               ? await item.handler.call()
               : await item.handler;
+          const position = state.stack_running.map(i => i === item ? i : -1).filter(i => i !== -1);
+          state.stack_running.splice(position, 1);
           state.running--;
           item.resolve.call(null, result);
           internal.pump();
         } catch (error) {
+          const position = state.stack_running.map(i => i === item ? i : -1).filter(i => i !== -1);
+          state.stack_running.splice(position, 1);
           state.running--;
           state.error = error;
           item.reject.call(null, error);