add $vars and $flow to custom function

packages/components/nodes/tools/CustomTool/core.ts

@@ -1,6 +1,6 @@
 import { z } from 'zod'
 import { NodeVM } from 'vm2'
-import { availableDependencies } from '../../../src/utils'
+import { availableDependencies, defaultAllowBuiltInDep, prepareSandboxVars } from '../../../src/utils'
 import { RunnableConfig } from '@langchain/core/runnables'
 import { StructuredTool, ToolParams } from '@langchain/core/tools'
 import { CallbackManagerForToolRun, Callbacks, CallbackManager, parseCallbackConfigArg } from '@langchain/core/callbacks/manager'
@@ -112,48 +112,13 @@ export class DynamicStructuredTool<
             }
         }
 
-        // inject variables
-        let vars = {}
-        if (this.variables) {
-            for (const item of this.variables) {
-                let value = item.value
-
-                // read from .env file
-                if (item.type === 'runtime') {
-                    value = process.env[item.name]
-                }
-
-                Object.defineProperty(vars, item.name, {
-                    enumerable: true,
-                    configurable: true,
-                    writable: true,
-                    value: value
-                })
-            }
-        }
-        sandbox['$vars'] = vars
+        sandbox['$vars'] = prepareSandboxVars(this.variables)
 
         // inject flow properties
         if (this.flowObj) {
             sandbox['$flow'] = { ...this.flowObj, ...flowConfig }
         }
 
-        const defaultAllowBuiltInDep = [
-            'assert',
-            'buffer',
-            'crypto',
-            'events',
-            'http',
-            'https',
-            'net',
-            'path',
-            'querystring',
-            'timers',
-            'tls',
-            'url',
-            'zlib'
-        ]
-
         const builtinDeps = process.env.TOOL_FUNCTION_BUILTIN_DEP
             ? defaultAllowBuiltInDep.concat(process.env.TOOL_FUNCTION_BUILTIN_DEP.split(','))
             : defaultAllowBuiltInDep