feat(transformer): add objectName+propertyName selector to #fromFunctionQuery (#58)

Author: crysmags

lib/transformer.js

@@ -245,7 +245,7 @@ class Transformer {
    * @returns {string} esquery selector.
    */
   #fromFunctionQuery (functionQuery) {
-    const { functionName, expressionName, className } = functionQuery
+    const { functionName, expressionName, className, objectName, propertyName } = functionQuery
     const type = functionQuery.privateMethodName ? 'PrivateIdentifier' : 'Identifier'
     const queries = []
 
@@ -281,6 +281,19 @@ class Transformer {
       )
     }
 
+    if (objectName || propertyName) {
+      if (!objectName || !propertyName) {
+        throw new Error(
+          `functionQuery: 'objectName' and 'propertyName' must be used together (got objectName=${objectName}, propertyName=${propertyName})`
+        )
+      }
+      const objectSelector = objectName === 'this'
+        ? 'left.object.type=ThisExpression'
+        : `left.object.name="${objectName}"`
+      queries.push(
+        `AssignmentExpression[${objectSelector}][left.property.name="${propertyName}"] > [async]`
+      )
+    }
     return queries.join(', ')
   }
 }

tests/object_property_named_cjs/mod.js

@@ -0,0 +1,10 @@
+'use strict'
+
+// Named object pattern: async arrow function assigned to a property
+// on a named identifier (not `this`).
+const conn = {}
+conn.query = async () => {
+  return 42
+}
+
+module.exports = { conn }

tests/object_property_named_cjs/test.js

@@ -0,0 +1,16 @@
+'use strict'
+
+const { conn } = require('./instrumented.js')
+const { assert, getContext } = require('../common/preamble.js')
+const context = getContext('orchestrion:undici:conn_query')
+
+;(async () => {
+  const result = await conn.query()
+  assert.strictEqual(result, 42)
+  assert.deepStrictEqual(context, {
+    start: true,
+    end: true,
+    asyncStart: 42,
+    asyncEnd: 42
+  })
+})()

tests/object_property_this_cjs/mod.js

@@ -0,0 +1,11 @@
+'use strict'
+
+// Mimics the mariadb v2 pattern: query methods are arrow functions
+// assigned to `this` inside a function constructor.
+function Connection (opts) {
+  this._query = async () => {
+    return 42
+  }
+}
+
+module.exports = { Connection }

tests/object_property_this_cjs/test.js

@@ -0,0 +1,17 @@
+'use strict'
+
+const { Connection } = require('./instrumented.js')
+const { assert, getContext } = require('../common/preamble.js')
+const context = getContext('orchestrion:undici:Connection_query')
+
+;(async () => {
+  const conn = new Connection({ host: 'localhost' })
+  const result = await conn._query()
+  assert.strictEqual(result, 42)
+  assert.deepStrictEqual(context, {
+    start: true,
+    end: true,
+    asyncStart: 42,
+    asyncEnd: 42
+  })
+})()

tests/tests.test.mjs

@@ -529,3 +529,27 @@ describe('IIFE with class', () => {
     ])
   })
 })
+
+describe('object_property_this_cjs', () => {
+  test('instruments async arrow function assigned to this inside a function constructor', () => {
+    runTest('object_property_this_cjs', [
+      {
+        channelName: 'Connection_query',
+        module: { name: TEST_MODULE_NAME, versionRange: '>=0.0.1', filePath: TEST_MODULE_PATH },
+        functionQuery: { objectName: 'this', propertyName: '_query', kind: 'Async' },
+      },
+    ])
+  })
+})
+
+describe('object_property_named_cjs', () => {
+  test('instruments async arrow function assigned to a named identifier property', () => {
+    runTest('object_property_named_cjs', [
+      {
+        channelName: 'conn_query',
+        module: { name: TEST_MODULE_NAME, versionRange: '>=0.0.1', filePath: TEST_MODULE_PATH },
+        functionQuery: { objectName: 'conn', propertyName: 'query', kind: 'Async' },
+      },
+    ])
+  })
+})