Dietary Preferences

The dietary preferences feature allows customers to set their dietary needs and allergen restrictions, automatically filtering menu items to show only what's suitable for them.

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Overview

Dietary preferences are managed entirely on the client side , no dietary data is sent to any server. This design ensures:

• Privacy: Customer dietary data never leaves their device.
• Speed: Filtering is instant, no network request needed.
• Offline support: Works even without internet connectivity.
• Guest-friendly: No login required to use the feature.

Preferences are stored in localStorage and persist across sessions on the same device.

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Setting Dietary Preferences

Accessing the Preferences Sheet

1. Tap the Sliders icon or Set allergies & dietary preferences link in the menu header.
2. The DietaryPreferencesSheet opens as a slide-over panel.

Configuring Preferences

The sheet has two sections:

Dietary Flags

Select dietary patterns you follow:

• Vegetarian
• Vegan
• Gluten-free
• Dairy-free
• Halal
• Keto
• Paleo
• Nut-free
• Sugar-free

Selecting a dietary flag positively filters items , only items tagged with matching dietary tags are shown.

Allergen Avoidances

Select allergens you need to avoid:

• Peanuts
• Tree nuts
• Milk
• Eggs
• Soy
• Wheat
• Fish
• Shellfish
• Sesame

Allergen selections trigger warnings or blocks depending on your strictness setting.

Strictness Level

Choose how allergen warnings behave:

Level	Behavior
Warn	Items containing selected allergens are highlighted with a warning indicator, but ordering is allowed
Block	Items containing selected allergens are greyed out and cannot be added to the cart

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How Filtering Works

Dietary Flags (Positive Filter)

• An item tagged as vegetarian will show when the customer selects Vegetarian.
• Items without the matching tag are not hidden , dietary flags only positively filter, they never exclude.

This design choice (documented in the codebase as an "honesty note"): "Absence of a tag is not proof , dietary flags are positive markers, so they never raise a false alarm."

Allergens (Warn/Block)

• Items with explicit allergen tags matching the customer's avoids are warned or blocked based on strictness.
• The blocking is based on the item's explicit allergens list.

Visual Indicators

On the public menu:

• Items that conflict with dietary preferences show a small warning badge.
• In "block" mode, affected items are visually dimmed.
• A summary chip in the header shows active dietary preferences.

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Signed-in Customers

Signed-in customers can optionally persist their dietary preferences to their account for cross-device restore:

1. Set preferences in the DietaryPreferencesSheet.
2. Sign in to your account.
3. Preferences are saved to your profile.
4. On another device, sign in to restore your preferences.

This is a convenience feature , the device-local profile always remains the primary source of truth.

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Implementation Details

• Hook: useDietaryProfile() , provides the current profile and update functions.
• Evaluation: evaluateItemDietary() , checks an item against the profile and returns match/warning/block status.
• Source of truth: localStorage (dietary_preferences key).
• No server storage: Dietary data is never sent to the API.

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Related Documentation

• Menu Items (Dietary Tags)
• Viewing a Menu
• Ordering Flow
• Customer Accounts