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Summary

Fixes #5650 - The Regex operation in Condition node was not implemented.

Changes

  • Added [regex]
    Flowise/packages/components/nodes/agentflow/Condition/Condition.ts:277:12-297:13) handler to compareOperationFunctions
  • Added [unescapeRegexPattern]
    Flowise/packages/components/nodes/agentflow/Condition/Condition.ts:278:16-288:17) helper to handle Flowise's escaping of metacharacters
  • Gracefully returns false for invalid regex patterns (no crashes)
  • Added 22 unit tests covering all scenarios

Test Coverage

  • All regex metacharacters: ^ $ [ ] . * + ? { } ( ) |
  • Flowise escaping scenarios
  • Invalid patterns (graceful failure)
  • Edge cases (null, empty values)

Known Limitation

Patterns matching markdown link syntax may be affected by existing removeMarkdown preprocessing.

The Condition agentflow node's Regex operation was not functional because
compareOperationFunctions was missing the regex handler.
Changes:
- Added regex handler with unescapeRegexPattern helper function
- Handles Flowise's escaping of regex metacharacters
- Gracefully returns false for invalid regex patterns
- Added 22 unit tests
Fixes FlowiseAI#5650
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Summary of Changes

Hello @Aadil-Hasun, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical missing feature in the Condition node within Agentflow by integrating a robust regular expression comparison handler. The implementation accounts for Flowise's automatic input escaping, ensuring that user-defined regex patterns are correctly interpreted. Furthermore, it enhances system stability by gracefully managing invalid regex inputs and is backed by a comprehensive suite of unit tests to guarantee reliability across various scenarios.

Highlights

  • Regex Handler Added: A new regex comparison operation has been implemented and added to the Condition node, enabling regular expression matching for conditional logic.
  • Flowise Escaping Handled: An unescapeRegexPattern helper function was introduced to correctly interpret regex patterns that Flowise's input handling might have automatically escaped (e.g., \[ for [).
  • Graceful Error Handling: The implementation now gracefully handles invalid regex patterns, preventing crashes and returning false for such cases.
  • Comprehensive Unit Tests: Twenty-two new unit tests have been added to ensure robust coverage of the regex functionality, including various metacharacters, Flowise-specific escaping scenarios, edge cases, and invalid patterns.
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Code Review

This pull request successfully adds the missing regex operation to the Condition node, including a comprehensive set of unit tests. The implementation correctly handles escaped characters from the Flowise UI and gracefully manages invalid regex patterns. My review includes a few suggestions to improve the implementation's correctness and robustness, as well as enhance the consistency and completeness of the new tests. Specifically, I've pointed out a potential bug in the regex unescaping logic and suggested improvements to the test structure and assertions.

const unescapeRegexPattern = (escaped: string): string => {
return escaped
.replace(/\\\\/g, '\0') // Preserve intentional backslashes (\\)
.replace(/\\([[\].*+?^${}()|])/g, '$1') // Unescape all regex metacharacters
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high

The set of metacharacters being unescaped here is too broad and can cause incorrect regex evaluation. According to the provided tests and description, Flowise only escapes [, ], and \. This implementation, however, unescapes many other metacharacters like ., *, +, ?, etc. This would cause a pattern like \. (intended to match a literal dot) to become ., which matches any character.

The unescaping should be restricted to only [ and ], as \ is already handled by the surrounding replace calls.

Suggested change
.replace(/\\([[\].*+?^${}()|])/g, '$1') // Unescape all regex metacharacters
.replace(/\([[\]])/g, '$1') // Unescape only brackets, as other metachars aren't escaped by Flowise

{ type: 'string', value1: null, operation: 'regex', value2: 'test' }
]
const result = await nodeClass.run(createConditionNodeData('test-null', conditions), '', { agentflowRuntime: { state: {} } })
expect(result.output.conditions[0].isFulfilled).toBeUndefined()
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medium

To make this test more robust and align with other tests for non-matching conditions (e.g., lines 44-45), you should also assert that the else condition is fulfilled.

            expect(result.output.conditions[0].isFulfilled).toBeUndefined()
            expect(result.output.conditions[1].isFulfilled).toBe(true)

{ type: 'string', value1: 'Hello', operation: 'regex', value2: 'hello' }
]
const result = await nodeClass.run(createConditionNodeData('test-case', conditions), '', { agentflowRuntime: { state: {} } })
expect(result.output.conditions[0].isFulfilled).toBeUndefined()
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medium

Similar to other tests for non-matching conditions, it would be good to also assert that the else condition is fulfilled to ensure the fallback logic is working as expected.

            expect(result.output.conditions[0].isFulfilled).toBeUndefined()
            expect(result.output.conditions[1].isFulfilled).toBe(true)


it('should handle ^ (start anchor)', async () => {
const conditions = [{ type: 'string', value1: 'hello world', operation: 'regex', value2: '^hello' }]
const result = await new Condition_Agentflow().run(createConditionNodeData('test-caret', conditions), '', { agentflowRuntime: { state: {} } })
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medium

For consistency with the other test suites in this file, please use the nodeClass instance created in the beforeEach block instead of creating a new Condition_Agentflow instance in each test. This should be applied to all tests within the 'Complex regex patterns - all metacharacters' describe block.

            const result = await nodeClass.run(createConditionNodeData('test-caret', conditions), '', { agentflowRuntime: { state: {} } })

- Move unescapeRegexPattern to module level for performance
- Restrict unescaping to only [, ], * (verified by UI testing)
- Use nodeClass from beforeEach in all tests for consistency
- Add else condition assertions for non-matching tests
- Add test for escaped asterisk
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Bug: "Regex" operation in Condition node is not implemented in backend

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