set up an event listener for outputs within useCell

src-tauri/src/main.rs

@@ -83,7 +83,10 @@ impl AppState {
 
                 let finished_output = &output_handler.lock().await.output;
 
-                window.emit("output", finished_output.clone()).unwrap();
+                window.emit(
+                    format!("cell-outputs-{}", cell_id).as_str(),
+                    Some(finished_output.clone()),
+                    ).unwrap();
                 return true;
             }
         }

src/components/Cell.tsx

@@ -4,12 +4,13 @@ import { useCell } from "@/hooks/useCell";
 import { Editor } from "@/components//Editor";
 
 const Cell = ({ cellId }: { cellId: string }) => {
-  const { executeCell, cellState, executionCount } = useCell(cellId);
+  const { executeCell, executionState, executionCount, outputs } =
+    useCell(cellId);
 
   let actionIcon = "▶";
   let showExecutionCountAs = executionCount === null ? " " : executionCount;
 
-  switch (cellState) {
+  switch (executionState) {
     case "idle":
     // Let them try again
     case "errored":
@@ -24,16 +25,25 @@ const Cell = ({ cellId }: { cellId: string }) => {
   }
 
   return (
-    <div className="bg-gray-100 p-4 rounded flex items-start">
-      <Button
-        variant="ghost"
-        className="font-mono text-sm group w-14 h-full pt-0 pb-0 m-0"
-        onClick={executeCell}
-      >
-        [<div className="group-hover:block hidden">{actionIcon}</div>
-        <span className="group-hover:hidden">{showExecutionCountAs}</span>]
-      </Button>
-      <Editor cellId={cellId} className="mr-2 pt-0 pb-0 text-sm" language="python"/>
+    <div>
+      <div className="bg-gray-100 p-4 rounded flex items-start">
+        <Button
+          variant="ghost"
+          className="font-mono text-sm group w-14 h-full pt-0 pb-0 m-0"
+          onClick={executeCell}
+        >
+          [<div className="group-hover:block hidden">{actionIcon}</div>
+          <span className="group-hover:hidden">{showExecutionCountAs}</span>]
+        </Button>
+        <Editor
+          cellId={cellId}
+          className="mr-2 pt-0 pb-0 text-sm"
+          language="python"
+        />
+      </div>
+      {outputs && outputs.length > 0 ? (
+        <pre>{JSON.stringify(outputs, null, 2)}</pre>
+      ) : null}
     </div>
   );
 };

src/hooks/useCell.ts

@@ -1,46 +1,82 @@
-import { useState, useCallback } from "react";
+import { useState, useEffect, useCallback, useReducer } from "react";
 import { invoke } from "@tauri-apps/api/tauri";
+import { listen } from '@tauri-apps/api/event'
 
-type CellStates = "idle" | "queued" | "busy" | "errored" | "submitted";
-
-export function useCell(cellId: string) {
-  const [content, setContent] = useState<string>("");
-
-  // We also find out the execution count, whether the cell is queued, busy, or
-  // errored, and the output of the cell. We can use this to display the
-  // execution count, a spinner, or an error message.
-
-  // Execution count is only set by the backend.
-
-  const executionCount = null; // TODO: get from backend
+enum ExecutionState {
+  Idle = "idle",
+  Queued = "queued",
+  Busy = "busy",
+  Errored = "errored",
+  Submitted = "submitted"
+}
 
-  // Queued, busy, and errored are set by the backend. However, we have to
-  // have our own state for queued for before the backend has acknowledged the
-  // execution request.
+type Action = { type: 'setSubmitted' } | { type: 'reset' } | {type: "setOutputs", outputs: []}
 
-  const [executionSubmitted, setExecutionSubmitted] = useState<boolean>(false);
+type CellState = {
+  executionState: ExecutionState;
+  outputs: [];
+}
 
-  let cellState: CellStates = "idle";
+const initialState: CellState = {
+  executionState: ExecutionState.Idle,
+  outputs: []
+};
 
-  if (executionSubmitted) {
-    cellState = "submitted";
+function cellReducer(state: CellState, action: Action) {
+  switch (action.type) {
+    case 'setSubmitted':
+      return { ...state, executionState: ExecutionState.Submitted };
+    case 'reset':
+      return { ...state, executionState: ExecutionState.Idle };
+    case 'setOutputs':
+      return {...state, outputs: action.outputs }
+    default:
+      return state;
   }
+}
 
+export function useCell(cellId: string) {
+  const [content, setContent] = useState<string>("");
+  const [state, dispatch] = useReducer(cellReducer, initialState);
+
   const executeCell = useCallback(async () => {
-    setExecutionSubmitted(true);
-    await invoke("execute_cell", { cellId });
-    setExecutionSubmitted(false);
+    dispatch({ type: 'setSubmitted' });
+    try {
+      await invoke("execute_cell", { cellId });
+    } catch (error) {
+      console.error(error);
+      // Handle error
+    }
+    dispatch({ type: 'reset' });
   }, [cellId]);
 
-  const updateCell = useCallback(
-    async (newContent: string) => {
+  const updateCell = useCallback(async (newContent: string) => {
+    try {
       await invoke("update_cell", { cellId, newContent });
       setContent(newContent);
-    },
-    [cellId]
-  );
+    } catch (error) {
+      console.error(error);
+      // Handle error
+    }
+  }, [cellId]);
+
+  useEffect(() => {
+    const setupListener = async () => {
+      const unlisten = await listen(`cell-outputs-${cellId}`, (event) => {
+        // Q(Kyle): Do we need to check if the event.windowLabel matches ours
+        const outputs = event.payload as [];
 
-  // TODO(kyle): Listen for events from the backend to update the cell content
+        dispatch({type: "setOutputs", outputs})
+
+      });
+
+      return () => {
+        unlisten();
+      };
+    };
+
+    setupListener();
+  }, [cellId]);
 
-  return { content, executeCell, updateCell, cellState: cellState as CellStates, executionCount };
+  return { ...state, content, executeCell, updateCell, executionCount: null};
 }

src/main.tsx

@@ -2,13 +2,7 @@ import React from "react";
 import ReactDOM from "react-dom/client";
 import App from "./App";
 import "./index.css";
-import { emit, listen } from '@tauri-apps/api/event'
 
-// listen to the `click` event and get a function to remove the event listener
-// there's also a `once` function that subscribes to an event and automatically unsubscribes the listener on the first event
-const unlisten = await listen('output', (event) => {
-  console.log(event)
-})
 
 ReactDOM.createRoot(document.getElementById("root") as HTMLElement).render(
   <React.StrictMode>