FluidForms | The Intelligent Intake Engine

FluidForms uses Liquid templating to create dynamic, intelligent forms. This guide covers everything you need to know about using Liquid expressions.

What is Liquid?

Liquid is a templating language that lets you insert dynamic content, perform calculations, and create conditional logic in your forms. Think of it as a simple programming language embedded in your form.

Where Can You Use Liquid?

Liquid expressions work in most string values throughout your form:

Field values (pre-fill or calculate)
Field visibility (hidden property)
Field validation (min/max properties)
Section navigation (go to section name)
Button labels
Field options (in some cases)

Important: Liquid does not work in field names or section names - these must be static strings.

Liquid Basics

Liquid has two types of markup:

Output Expressions `{{ }}`

Display or insert values. The result is rendered to users.

{{ firstName }}
Total: ${{ price | times: quantity }}

Tags `{% %}`

Control flow and logic. These don't directly render output.

{% if age >= 18 %}
  Adult content
{% endif %}

{% assign total = price | times: quantity %}

Accessing Form Data

Field values are available directly by their Field Name.

{{ firstName }}
{{ email }}

Note: Ensure your field names are unique and do not conflict with built-in variables.

Built-in Variables

FluidForms provides helpful built-in variables:

{{ now }}    // Current date and time in ISO format
{{ today }}  // Current date in YYYY-MM-DD format

Examples

Application Date: {{ today }}
Expires: {{ today | add_time: 30, 'day' | format_date: 'YYYY-MM-DD' }}
Submitted at: {{ now }}

Control Flow

if / elsif / else / endif

Conditional logic for making decisions:

{% if membership == 'Gold' %}
  You receive 20% off
{% elsif membership == 'Silver' %}
  You receive 10% off
{% else %}
  No discount available
{% endif %}

unless / endunless

The opposite of if - executes when condition is false:

{% unless subscribed %}
  Sign up for our newsletter!
{% endunless %}

for / endfor

Loop over arrays:

{% for item in cart %}
  - {{ item.name }}: ${{ item.price }}
{% endfor %}

Loop parameters:

{% for item in items limit:3 %}    // First 3 items
{% for item in items offset:2 %}   // Skip first 2
{% for item in items reversed %}   // Reverse order
{% for i in (1..5) %}                     // Range from 1 to 5

liquid tag

Write multiple statements without repeating delimiters:

{% liquid
  assign price = 100
  assign tax = price | times: 0.1
  assign total = price | plus: tax
  echo total
%}

Filters

Filters modify values using the pipe | operator:

{{ "hello" | capitalize }}    // Hello
{{ 4.6 | round }}            // 5
{{ items | size }}    // Number of items

Math Filters

{{ 10 | plus: 5 }}           // 15
{{ 10 | minus: 3 }}          // 7
{{ 10 | times: 2 }}          // 20
{{ 10 | divided_by: 2 }}     // 5
{{ 10 | modulo: 3 }}         // 1
{{ 4.6 | round }}            // 5
{{ 4.2 | ceil }}             // 5
{{ 4.9 | floor }}            // 4
{{ -5 | abs }}               // 5
{{ 3 | at_least: 5 }}        // 5 (minimum)
{{ 10 | at_most: 5 }}        // 5 (maximum)

String Filters

{{ "hello" | capitalize }}              // Hello
{{ "hello" | upcase }}                  // HELLO
{{ "HELLO" | downcase }}                // hello
{{ "  hello  " | strip }}               // hello
{{ "Long text here" | truncate: 8 }}    // Long ...
{{ "One two three" | truncatewords: 2 }}// One two...
{{ "hello" | replace: "h", "j" }}       // jello
{{ "a,b,c" | split: "," }}             // ['a','b','c']
{{ tags | join: ", " }}          // tag1, tag2, tag3
{{ "hello" | size }}                    // 5

Array Filters

{{ items | first }}                         // First item
{{ items | last }}                          // Last item
{{ items | size }}                          // Number of items
{{ items | join: ", " }}                    // Join array to string
{{ products | map: "name" }}                // Extract property
{{ products | where: "available", true }}   // Filter by property
{{ items | sort }}                          // Sort (case-sensitive)
{{ items | sort_natural }}                  // Sort (case-insensitive)
{{ tags | uniq }}                           // Remove duplicates
{{ arr1 | concat: arr2 }}            // Combine arrays
{{ items | compact }}                       // Remove nil values

Essential Filters

{{ name | default: "Guest" }}     // Fallback for empty values
{{ "42" | plus: 0 }}                     // Convert string to number
{{ object | json }}               // Convert to JSON string
{{ object | json: 2 }}            // JSON with indentation

Date/Time Filters (Custom)

// Add time to a date
{{ someDate | add_time: 7, "day" }}
{{ today | add_time: 1, "year" }}

// Subtract time from a date
{{ someDate | subtract_time: 18, "year" }}
{{ now | subtract_time: 30, "minute" }}

// Format a date
{{ someDate | format_date: "YYYY-MM-DD" }}
{{ now | format_date: "MMM DD, YYYY" }}

// Get start of time period
{{ now | start_of: "day" }}
{{ someDate | start_of: "month" }}

// Compare dates
{{ date1 | is_before: date2 }}       // true/false
{{ date1 | is_after }}               // true/false (compares to now)
{{ date | is_between: start, end }}  // true/false

// Calculate difference
{{ birthDate | diff_time: today, "year" }}    // Age in years
{{ deadline | diff_time: now, "day" }}        // Days until deadline

// Human-readable relative time
{{ someDate | time_from }}           // "2 hours ago"
{{ futureDate | time_from }}         // "in 3 days"

Time units: "year", "month", "week", "day", "hour", "minute", "second"

Practical Examples

Example 1: Age Calculation

{% assign age = birthDate | diff_time: today, "year" %}
Age: {{ age }}

{% if age >= 18 %}
  You are eligible to vote
{% else %}
  You will be eligible in {{ 18 | minus: age }} years
{% endif %}

Example 2: Discount Calculation

{% liquid
  assign basePrice = price | default: 0
  assign quantity = quantity | default: 1
  assign subtotal = basePrice | times: quantity

  if membershipType == "gold"
    assign discount = 0.2
  elsif membershipType == "silver"
    assign discount = 0.1
  else
    assign discount = 0
  endif

  assign discountAmount = subtotal | times: discount
  assign total = subtotal | minus: discountAmount
%}

Subtotal: ${{ subtotal }}
Discount: ${{ discountAmount }}
Total: ${{ total }}

Example 3: Conditional Navigation

{% liquid
  assign age = birthDate | diff_time: today, "year"
  assign hasGuardian = hasGuardian | default: "no"

  if age < 18 and hasGuardian != "yes"
    echo "guardian-required"
  elsif age < 18
    echo "minor-section"
  else
    echo "adult-section"
  endif
%}

Example 4: Dynamic Validation

Field: Event Date

Minimum: {{ today | add_time: 1, "day" | format_date: "YYYY-MM-DD" }}
Maximum: {{ today | add_time: 1, "year" | format_date: "YYYY-MM-DD" }}

Example 5: Multi-field Summary

{% liquid
  assign items = selectedItems
  assign itemNames = items | map: "name" | join: ", "
  assign itemCount = items | size
  assign totalPrice = 0

  for item in items
    assign totalPrice = totalPrice | plus: item.price
  endfor
%}

You selected {{ itemCount }} items: {{ itemNames }}
Total: ${{ totalPrice }}

Example 6: Conditional Field Display

Field: Additional Information

Hidden:
{% if needsMoreInfo == "yes" %}
  false
{% else %}
  true
{% endif %}

Advanced Patterns

Pattern 1: Complex Calculations with Variables

{% liquid
  assign income = annual_income | plus: 0
  assign expenses = monthly_expenses | plus: 0 | times: 12
  assign netIncome = income | minus: expenses
  assign savingsRate = netIncome | divided_by: income | times: 100

  if savingsRate >= 20
    assign savingsLevel = "Excellent"
  elsif savingsRate >= 10
    assign savingsLevel = "Good"
  else
    assign savingsLevel = "Needs Improvement"
  endif
%}

Your savings rate: {{ savingsRate | round: 1 }}%
Level: {{ savingsLevel }}

Pattern 2: Date Range Validation

{% liquid
  assign start = start_date
  assign end = end_date
  assign duration = end | diff_time: start, "day"

  if duration < 0
    echo "End date must be after start date"
  elsif duration > 365
    echo "Duration cannot exceed 1 year"
  else
    echo "Duration: " | append: duration | append: " days"
  endif
%}

Pattern 3: Scoring System

{% liquid
  assign score = 0

  if experience == "5+ years"
    assign score = score | plus: 30
  elsif experience == "3-5 years"
    assign score = score | plus: 20
  elsif experience == "1-3 years"
    assign score = score | plus: 10
  endif

  if education == "Masters"
    assign score = score | plus: 20
  elsif education == "Bachelors"
    assign score = score | plus: 10
  endif

  if certifications | size > 0
    assign certCount = certifications | size
    assign certPoints = certCount | times: 5 | at_most: 20
    assign score = score | plus: certPoints
  endif
%}

Your qualification score: {{ score }}/100

Best Practices

1. Use Variables for Clarity

❌ Bad:

{{ price | times: quantity | times: 1.1 | plus: 5 }}

✅ Good:

{% liquid
  assign subtotal = price | times: quantity
  assign withTax = subtotal | times: 1.1
  assign total = withTax | plus: 5
%}
Total: ${{ total }}

2. Provide Fallbacks

❌ Bad:

{{ price | times: quantity }}

✅ Good:

{{ price | default: 0 | times: quantity | default: 1 }}

3. Validate with Static Field Names

❌ Bad:

// Field label: "Customer's Email"
{{ values['Customer\'s Email'] }}

✅ Good:

// Field label: "Customer's Email"
// Field name: email
{{ email }}

4. Keep Expressions Simple

❌ Bad:

{% if a and b or c and not d or e %}

✅ Good:

{% liquid
  assign conditionA = false
  if a and b
    assign conditionA = true
  endif

  assign conditionB = false
  if c and d != true
    assign conditionB = true
  endif

  if conditionA or conditionB or e
    echo "condition-met"
  endif
%}

Common Pitfalls

1. Using Output Instead of Tag

❌ {{ if age >= 18 }}
✅ {% if age >= 18 %}

2. Forgetting to Close Tags

❌ {% if condition %} content
✅ {% if condition %} content {% endif %}

3. Wrong Variable Access

❌ {{ values.firstName }}
✅ {{ firstName }}

4. String Concatenation

❌ {{ "Hello " + name }}
✅ {{ "Hello " | append: name }}

5. Missing Default Values

❌ {{ price | times: quantity }}
✅ {{ price | default: 0 | times: quantity | default: 1 }}

Next Steps

Logic & Branching - Apply Liquid to create dynamic forms
Fields - See where Liquid can be used
Advanced Logic - Advanced customization options
Troubleshooting Guide - Solutions for common issues

Liquid Templates

What is Liquid?

Where Can You Use Liquid?

Liquid Basics

Output Expressions {{ }}

Tags {% %}

Accessing Form Data

Built-in Variables

Examples

Control Flow

if / elsif / else / endif

unless / endunless

for / endfor

liquid tag

Filters

Math Filters

String Filters

Array Filters

Essential Filters

Date/Time Filters (Custom)

Practical Examples

Example 1: Age Calculation

Example 2: Discount Calculation

Example 3: Conditional Navigation

Example 4: Dynamic Validation

Example 5: Multi-field Summary

Example 6: Conditional Field Display

Advanced Patterns

Pattern 1: Complex Calculations with Variables

Pattern 2: Date Range Validation

Pattern 3: Scoring System

Best Practices

1. Use Variables for Clarity

2. Provide Fallbacks

3. Validate with Static Field Names

4. Keep Expressions Simple

Common Pitfalls

1. Using Output Instead of Tag

2. Forgetting to Close Tags

3. Wrong Variable Access

4. String Concatenation

5. Missing Default Values

Next Steps

Output Expressions `{{ }}`

Tags `{% %}`