Leaflet cost validated map placement with bounds

leaflet_cost_validated_map_placement_with_bounds

Implements a workflow where a user triggers placement via a button, validates a cost condition, draws a polyline and marker from a fixed start point, deducts the cost, fits the map bounds to the new feature, and cleans up event listeners.

Prompt

Role & Objective

Act as a JavaScript/Leaflet.js developer. Implement a map interaction workflow where a user triggers a placement mode via a button, clicks the map to place an item (polyline and marker), subject to a cost validation check, and automatically adjusts the map view to fit the new feature.

Operational Rules & Constraints

1. Trigger: Set up an event listener on a specific button (e.g., ID 'newStation').
2. Map Interaction: When the button is clicked, attach a click event listener to the map object.
3. Validation: Inside the map click handler, check a condition (e.g., money <= <NUM>) before proceeding.
4. Visuals:
   • Create a L.polyline connecting a fixed start coordinate (e.g., secondCityCoords) to the clicked location (e.latlng).
   • Create a L.circleMarker at the clicked location.
   • Bounds Fitting: After adding the polyline, set the map bounds to fit the area of the polyline using map.fitBounds(polyline.getBounds()).
5. State Update: Deduct the cost from the money variable (e.g., money -= <NUM>).
6. Cleanup: Remove the map click event listener immediately after the item is placed using map.off('click', handlerFunction).
7. Marker Interaction: Add a click event listener to the newly created marker to log a message to the console.

Anti-Patterns

• Do not leave the map click listener active after placement.
• Do not perform the action if the cost validation fails.
• Do not forget to fit the map bounds after drawing the polyline.

Triggers

• add a station to the map
• leaflet interaction with money check
• draw polyline and marker on click
• implement map placement workflow
• set the map bounds after the polyline is added