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Variable Interpolation

Use {{fieldId}} to insert dynamic values into labels, help text, and info blocks.

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Basic Usage

Reference any field’s value: 
{
  "type": "info",
  "content": {
    "en": "Thanks, {{full-name}}! Based on your income of ${{annual-income}}, you may qualify for assistance."
  }
}

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Supported Locations

LocationExample
Labels"Hello, {{name}}"
Help text"Enter your address in {{city}}"
Info blocks"Based on {{income}}, you qualify"
Validation messages"{{field}} is required"

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Implementation

function interpolate(
  template: string,
  formData: Record<string, unknown>
): string {
  return template.replace(/\{\{([^}]+)\}\}/g, (match, fieldId) => {
    const value = formData[fieldId];
    if (value === undefined || value === null) return "";
    return String(value);
  });
}

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Common Patterns

Personalized greeting: 
Welcome back, {{first-name}}!
Dynamic eligibility: 
Households of {{household-size}} people may qualify for up to ${{max-benefit}}.
Confirmation summary: 
You entered {{address-line-1}}, {{city}}, {{state}} {{zip}}.

Translations

Multi-language support