laverdet
Execution returns `Reference {}` instead of actual result values
I'm using isolated-vm to create a secure execution environment for user-provided code. When executing code within an isolate, the result is not properly accessible from the main context. Instead of returning the actual result value, I'm getting a Reference {} object.
Code Example:
1 const ivm = require('isolated-vm');
2
3 async function test() {
4 const isolate = new ivm.Isolate({ memoryLimit: 128 });
5 const context = await isolate.createContext();
6
7 const jail = context.global;
8 await jail.set('global', jail.derefInto());
9 await jail.set('_result', null);
10 11 const code = ` 12 (function() {
13 const $input = _input;
14 let items = [];
15 if (Array.isArray($input)) {
16 items = $input.map(data => ({ json: data }));
17 } else {
18 items = [{ json: $input }];
19 }
20
21 // User code that should assign to result
22 result = { processed: true, data: items };
23
24 // Set the final result
25 if (typeof result !== 'undefined') {
26 _result = { result: result, logs: [] };
27 } else {
28 _result = { result: items, logs: [] };
29 }
30 })();
31 `;
32
33 const inputData = { userId: "test-user" };
34 await jail.set('_input', new ivm.ExternalCopy(inputData).copyInto());
35
36 await context.eval(code);
37
38 // This returns a Reference {} instead of the actual value
39 const result = await context.global.get('_result');
40 console.log('Result type:', typeof result, result); // Shows: Result type: object [Reference {}]
41
42 // This should work to get the actual value but returns {} for some reason
43 const actualResult = await result.copy();
44 console.log('Actual result:', actualResult); // Shows: Actual result: {}
45 }
46
47 test();
Expected Behavior: When calling context.global.get('_result') followed by .copy(), I expect to get the actual object that was assigned to _result within the isolate context (e.g., { result: { processed: true, data: [ /* ... */ ] }, logs: [] }).
Actual Behavior:
- context.global.get('_result') returns a Reference {} object
- result.copy() returns an empty object {} instead of the expected result
Environment:
- Node.js: v20.x
- isolated-vm: 6.0.2
- OS: Windows 10/11
What I've tried:
- Using result.copy() as suggested in documentation
- Different execution contexts
- Various approaches to setting and getting the result variable
Questions:
- Am I using the correct approach to extract values from the isolate context?
- Is there an issue with how the result is being assigned in the isolated context?
- Are there any limitations or special considerations for returning complex objects from isolated contexts?
When I run your example I get:
Result type: object Reference {}
Actual result: { result: { processed: true, data: [ [Object] ] }, logs: [] }
This seems to be the expected result?
When I run your example I get:
Result type: object Reference {} Actual result: { result: { processed: true, data: [ [Object] ] }, logs: [] }This seems to be the expected result?
The issue was that when i used isolated-vm, the result value was being retrieved from the isolate context as a
Reference object, but was not being properly copied to the main context using the .copy() method. This is what caused the
result to remain as an empty {} object instead of the actual execution result... i solved it buh thanks fren.