chore: refactor debugger snapshot collector code (#6921)

Rename a few function names that were ambiguous.

Author: watson

packages/dd-trace/src/debugger/devtools_client/snapshot/collector.js

@@ -7,7 +7,7 @@ const LEAF_SUBTYPES = new Set(['date', 'regexp'])
 const ITERABLE_SUBTYPES = new Set(['map', 'set', 'weakmap', 'weakset'])
 
 module.exports = {
-  getRuntimeObject: getObject
+  collectObjectProperties
 }
 
 /**
@@ -22,7 +22,7 @@ module.exports = {
  */
 
 /**
- * Get the properties of an object using the Chrome DevTools Protocol.
+ * Collect the properties of an object using the Chrome DevTools Protocol.
  *
  * @param {string} objectId - The ID of the object to get the properties of
  * @param {GetObjectOptions} opts - The options for the snapshot. Also used to track the deadline and communicate the
@@ -33,7 +33,7 @@ module.exports = {
  *   track the current object type and should not be set by the caller.
  * @returns {Promise<Object[]>} The properties of the object
  */
-async function getObject (objectId, opts, depth = 0, collection = false) {
+async function collectObjectProperties (objectId, opts, depth = 0, collection = false) {
   const { result, privateProperties } = await session.post('Runtime.getProperties', {
     objectId,
     ownProperties: true // exclude inherited properties
@@ -76,7 +76,7 @@ async function traverseGetPropertiesResult (props, opts, depth) {
       if (LEAF_SUBTYPES.has(subtype)) continue // don't waste time with these subtypes
       work.push([
         prop.value,
-        () => getObjectProperties(subtype, objectId, opts, depth).then((properties) => {
+        () => collectPropertiesBySubtype(subtype, objectId, opts, depth).then((properties) => {
           prop.value.properties = properties
         })
       ])
@@ -113,7 +113,7 @@ async function traverseGetPropertiesResult (props, opts, depth) {
   return props
 }
 
-function getObjectProperties (subtype, objectId, opts, depth) {
+function collectPropertiesBySubtype (subtype, objectId, opts, depth) {
   if (ITERABLE_SUBTYPES.has(subtype)) {
     return getIterable(objectId, opts, depth)
   } else if (subtype === 'promise') {
@@ -123,7 +123,7 @@ function getObjectProperties (subtype, objectId, opts, depth) {
   } else if (subtype === 'arraybuffer') {
     return getArrayBuffer(objectId, opts, depth)
   }
-  return getObject(objectId, opts, depth + 1, subtype === 'array' || subtype === 'typedarray')
+  return collectObjectProperties(objectId, opts, depth + 1, subtype === 'array' || subtype === 'typedarray')
 }
 
 // TODO: The following extra information from `internalProperties` might be relevant to include for functions:

packages/dd-trace/src/debugger/devtools_client/snapshot/index.js

@@ -1,6 +1,6 @@
 'use strict'
 
-const { getRuntimeObject } = require('./collector')
+const { collectObjectProperties } = require('./collector')
 const { processRawState } = require('./processor')
 const log = require('../log')
 
@@ -65,8 +65,11 @@ async function getLocalStateForCallFrame (
       if (scope.type === 'global') continue // The global scope is too noisy
       const { objectId } = scope.object
       if (objectId === undefined) continue // I haven't seen this happen, but according to the types it's possible
+      // The objectId for a scope points to a pseudo-object whos properties are the actual variables in the scope.
+      // This is why we can just call `collectObjectProperties` directly and expect it to return the in-scope variables
+      // as an array.
       // eslint-disable-next-line no-await-in-loop
-      rawState.push(...await getRuntimeObject(objectId, opts))
+      rawState.push(...await collectObjectProperties(objectId, opts))
       if (opts.ctx.deadlineReached === true) break // TODO: Bad UX; Variables in remaining scopes are silently dropped
     }
   } catch (err) {