Advanced Validation Expressions Guide

Documentation Index

Fetch the complete documentation index at: https://docs.encoreos.io/llms.txt

Use this file to discover all available pages before exploring further.

User guide for creating powerful validation rules using expression-based validation in wizard steps.

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Overview

• Age requirements
• Date comparisons
• Conditional required fields
• Pattern matching
• Cross-field validation
• Custom business rules

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Getting Started

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Accessing Expression Validation

1. Open a wizard template in the Builder
2. Select a step
3. Go to the Validation tab
4. Click the Advanced Expressions sub-tab

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Your First Expression

age(date_of_birth) >= 18

• Takes the date_of_birth field value
• Calculates the age in years
• Checks if it’s 18 or older

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Expression Syntax

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Basic Structure

function(field_name) operator value

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Operators

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Combining Expressions

// Both must be true
age(dob) >= 18 && !is_empty(email)

// Either can be true
is_empty(phone) || is_valid_phone(phone)

// Complex combination
(age(dob) >= 18 && is_employed) || has_guardian_consent

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Available Functions

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Date Functions

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String Functions

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Validation Functions

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Number Functions

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Comparison Functions

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Conditional Functions

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Common Patterns

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Age Verification

// Must be 18 or older
age(date_of_birth) >= 18

// Must be between 18 and 65
is_between(age(date_of_birth), 18, 65)

// Under 18 requires guardian
age(date_of_birth) >= 18 || !is_empty(guardian_name)

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Date Range Validation

// End date must be after start date
is_after(end_date, start_date)

// Event must be in the future
is_after(event_date, today())

// Must be within 90 days
days_since(submission_date) <= 90

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Conditional Required Fields

// Employer required if employed
required_if(is_employed, employer_name)

// Phone OR email required
!is_empty(phone) || !is_empty(email)

// Address required if not same as billing
required_if(!same_as_billing, shipping_address)

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Format Validation

// US phone format (10 digits)
matches(phone, "^\\d{10}$")

// ZIP code (5 or 9 digits)
matches(zip, "^\\d{5}(-\\d{4})?$")

// Strong password (8+ chars, number, special)
len(password) >= 8 && matches(password, "[0-9]") && matches(password, "[!@#$%]")

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Cross-Field Validation

// Confirm password matches
password == confirm_password

// Total must equal sum of parts
total == (subtotal + tax)

// End date at least 30 days after start
days_since(start_date) >= 30 || is_after(end_date, start_date)

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Creating Expression Rules

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Step-by-Step

1. Open Validation Panel: Select a step and click “Validation” tab
2. Switch to Advanced: Click “Advanced Expressions” sub-tab
3. Add Rule: Click “Add Expression Rule”
4. Write Expression: Enter your validation expression
5. Set Error Message: Define the message shown when validation fails
6. Set Timing: Choose when to validate (on change, blur, or submit)
7. Test: Use the Test Runner to verify

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Rule Properties

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Testing Expressions

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Using the Test Runner

1. Click Test Expressions button
2. Enter sample values for each field
3. Click Run Tests
4. View pass/fail results for each rule

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Test Runner Features

• Field Inputs: Auto-generated from step fields
• Quick Fill: Sample data suggestions
• Results Panel: Shows which rules pass/fail
• Error Preview: See exact error messages

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Testing Tips

1. Test both valid and invalid inputs
2. Test edge cases (empty, null, boundaries)
3. Test with realistic data
4. Verify error messages are helpful

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Error Messages

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Writing Good Messages

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Message Variables

"Age {{age(date_of_birth)}} does not meet the minimum requirement of 18"

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Best Practices

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Expression Design

1. Keep It Simple: Break complex rules into multiple expressions
2. Be Specific: Target specific fields, not entire forms
3. Handle Empty: Always consider null/empty cases
4. Use Parentheses: Make precedence explicit

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Performance

1. Timing Matters: Use on_submit for expensive validations
2. Avoid Redundancy: Don’t repeat standard validations
3. Order by Priority: Put quick-fail checks first

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Maintenance

1. Document Rules: Use clear error messages as documentation
2. Group Related Rules: Keep related validations together
3. Test After Changes: Always re-test after modifications
4. Version Control: Track changes in template versions

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Healthcare & PHI Compliance

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PHI Field Naming Guidelines

1. Use Generic Field Names: Prefer patient_id, resident_id, client_id over revealing field names
2. Avoid Revealing Names: Never use field names that expose sensitive data types (avoid ssn, medical_record_number, diagnosis_code)

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Expression Audit Requirements

1. Reviewed by a compliance officer before deployment
2. Logged for creation/modification with user ID and timestamp
3. Never log actual PHI values - only log field references and expression text

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Error Message Rules (Critical)

• Never include actual field values in error messages
• Use generic messages: “Age requirement not met” not “Your age of 17 does not meet…”
• Avoid revealing field contents in validation failures

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Timing Recommendations for PHI

• Use on_submit: For PHI field validations to minimize data exposure during typing
• Avoid on_change: Real-time validation can increase attack surface

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Access Control

• Only users with appropriate permissions should edit expressions
• Expression editing should be restricted to form administrators
• Implement retention policies for expression audit logs (recommended: 7 years for healthcare)

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Security Considerations

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Safe by Design

• No eval() or code execution
• No access to global objects
• No network requests
• No file system access

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What’s Blocked

• JavaScript code injection
• Function definitions
• Variable assignments
• External references

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What’s Allowed

• Field references by name
• Approved validation functions
• Operators (comparison, logical)
• Literal values (strings, numbers, booleans)

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Troubleshooting

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Common Errors

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Debugging Tips

1. Simplify: Reduce to smallest failing case
2. Test Runner: Use to isolate issues
3. Check Field Names: Match exactly (case-sensitive)
4. Review Syntax: Watch for missing quotes/parentheses

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See Also

• Wizard Builder Documentation
• Marketplace Guide