Reduce the amount of data sent back to JS/TS from WASM

src/lang/wasm.ts

@@ -35,7 +35,7 @@ import { Configuration } from 'wasm-lib/kcl/bindings/Configuration'
 import { DeepPartial } from 'lib/types'
 import { ProjectConfiguration } from 'wasm-lib/kcl/bindings/ProjectConfiguration'
 import { Sketch } from '../wasm-lib/kcl/bindings/Sketch'
-import { ExecState as RawExecState } from '../wasm-lib/kcl/bindings/ExecState'
+import { ExecOutcome } from 'wasm-lib/kcl/bindings/ExecOutcome'
 import { ProgramMemory as RawProgramMemory } from '../wasm-lib/kcl/bindings/ProgramMemory'
 import { EnvironmentRef } from '../wasm-lib/kcl/bindings/EnvironmentRef'
 import { Environment } from '../wasm-lib/kcl/bindings/Environment'
@@ -260,10 +260,10 @@ export function emptyExecState(): ExecState {
   }
 }
 
-function execStateFromRaw(raw: RawExecState): ExecState {
+function execStateFromRust(execOutcome: ExecOutcome): ExecState {
   return {
-    memory: ProgramMemory.fromRaw(raw.modLocal.memory),
-    operations: raw.modLocal.operations,
+    memory: ProgramMemory.fromRaw(execOutcome.memory),
+    operations: execOutcome.operations,
   }
 }
 
@@ -535,14 +535,14 @@ export const _executor = async (
         jsAppSettings = getAllCurrentSettings(lastSettingsSnapshot)
       }
     }
-    const execState: RawExecState = await execute(
+    const execOutcome: ExecOutcome = await execute(
       JSON.stringify(node),
       JSON.stringify(programMemoryOverride?.toRaw() || null),
       JSON.stringify({ settings: jsAppSettings }),
       engineCommandManager,
       fileSystemManager
     )
-    return execStateFromRaw(execState)
+    return execStateFromRust(execOutcome)
   } catch (e: any) {
     console.log(e)
     const parsed: KclErrorWithOutputs = JSON.parse(e.toString())

src/wasm-lib/kcl/src/execution/mod.rs

@@ -94,6 +94,18 @@ pub struct ModuleState {
     pub settings: MetaSettings,
 }
 
+/// Outcome from executing a program.  This is used in WebAssembly/WASM.
+#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema)]
+#[ts(export)]
+#[serde(rename_all = "camelCase")]
+pub struct ExecOutcome {
+    /// Program variable bindings of the top-level module.
+    pub memory: ProgramMemory,
+    /// Operations that have been performed in execution order, for display in
+    /// the Feature Tree.
+    pub operations: Vec<Operation>,
+}
+
 impl Default for ExecState {
     fn default() -> Self {
         Self::new()
@@ -123,6 +135,25 @@ impl ExecState {
         };
     }
 
+    /// Convert to an output for WebAssembly/WASM.
+    pub fn to_wasm_outcome(mut self) -> ExecOutcome {
+        // Clear closed-over program memory inside closures.  This is
+        // destructive.  It greatly reduces the amount of data crossing the WASM
+        // boundary that we won't ever use.
+        for env in self.mut_memory().environments.iter_mut() {
+            for (_, value) in env.bindings.iter_mut() {
+                if let KclValue::Function { memory, .. } = value {
+                    *memory = Box::new(ProgramMemory::new());
+                }
+            }
+        }
+
+        ExecOutcome {
+            memory: self.mod_local.memory,
+            operations: self.mod_local.operations,
+        }
+    }
+
     pub fn memory(&self) -> &ProgramMemory {
         &self.mod_local.memory
     }

src/wasm-lib/src/wasm.rs

@@ -133,7 +133,7 @@ pub async fn execute(
     // gloo-serialize crate instead.
     // DO NOT USE serde_wasm_bindgen::to_value(&exec_state).map_err(|e| e.to_string())
     // it will break the frontend.
-    JsValue::from_serde(&exec_state).map_err(|e| e.to_string())
+    JsValue::from_serde(&exec_state.to_wasm_outcome()).map_err(|e| e.to_string())
 }
 
 // wasm_bindgen wrapper for execute