Node.js Push方法结果异常：Alexa Skill Lambda代码求助

Hey John, let’s break down the two issues you’re facing with your Lambda code—one related to how JavaScript handles objects, and another about your return format.

Why Your push() Result Isn’t What You Expect #

The core problem here is how JavaScript treats objects: they’re reference types. When you push model2 into result.endpoints, you aren’t adding a copy of the object—you’re adding a pointer to the exact same object stored in memory.

Let’s walk through your code step by step to see what happens:

• You create model2 = {"endpointid": "stuff"}
• You update model2.endpointid to "switch1" and push this reference into the array
• Then you change model2.endpointid to "switch2"—this modifies the same object that’s already in your array
• You push that same reference again into the array

By the end, both entries in result.endpoints point to the same model2 object, so both show "endpointid": "switch2".

Fixing the Array Behavior #

To get two unique endpoints in your array, you need to create a new object each time you add an entry. Here are two straightforward ways to do this:

Option 1: Create a fresh object for each endpoint #

Instead of reusing model2, initialize a new object every time you need a new endpoint:

exports.handler = function(event, context) { 
  // Initialize your base model
  var model1 = {"endpoints": []}; 
  
  // Create first endpoint and add to array
  var switch1 = {"endpointid": "switch1"}; 
  model1.endpoints.push(switch1); 
  
  // Create second endpoint and add to array
  var switch2 = {"endpointid": "switch2"}; 
  model1.endpoints.push(switch2); 
  
  var json = JSON.stringify(model1); 
  context.succeed({json}); 
};

Option 2: Copy the base object before modifying #

If you want to reuse a base endpoint structure, use the spread operator (...) to make a shallow copy of the object before updating its properties:

exports.handler = function(event, context) { 
  var model1 = {"endpoints": []}; 
  // Base endpoint template
  var baseEndpoint = {"endpointid": "stuff"}; 
  
  // Make a copy, update, push
  var switch1 = {...baseEndpoint};
  switch1.endpointid = "switch1";
  model1.endpoints.push(switch1); 
  
  // Make another copy, update, push
  var switch2 = {...baseEndpoint};
  switch2.endpointid = "switch2";
  model1.endpoints.push(switch2); 
  
  var json = JSON.stringify(model1); 
  context.succeed({json}); 
};

Fixing Your Return Format #

You mentioned your result comes back as { "json": "{..." }—that’s because you’re wrapping the stringified JSON in an object with a json key.

If you want to return the actual JSON object directly (which is usually what Alexa Skills expect), you can skip JSON.stringify and pass model1 straight to context.succeed:

context.succeed(model1);

This will return a clean JSON structure like:

{
  "endpoints": [
    {"endpointid": "switch1"},
    {"endpointid": "switch2"}
  ]
}

If you specifically need to return a stringified JSON inside the json key (for a specific Skill requirement), then your original approach is fine—just double-check that’s what the Alexa service expects.

内容的提问来源于stack exchange，提问作者John