Tasks Overview

Tasks provide chainable operations for querying and analyzing Esri services, modeled after Esri Leaflet's task pattern.

Pattern

Tasks follow a create → configure → execute pattern:

const results = await new IdentifyFeatures({ url: '...' })
  .layers([0, 1, 2])
  .tolerance(5)
  .returnGeometry(true)
  .at({ lng: -95, lat: 37 }, map);

Available Tasks

Task	Description
IdentifyFeatures	Identify features at a point across map services
IdentifyImage	Get pixel values from image services
Query	Spatial and attribute queries with pagination
Find	Text-based search across layers and fields

Task vs Service Methods

Aspect	Task	Service Method
Flexibility	Highly configurable	Basic options
Chaining	Fluent API	Single call
Reusability	Reusable instances	One-time use

Common Patterns

Reusable Tasks

const queryTask = new Query({ url: '...' })
  .outFields(['*'])
  .returnGeometry(true);

const all = await queryTask.where('1=1').run();
const filtered = await queryTask.where('POP > 100000').run();

Error Handling

try {
  const results = await task.run();
} catch (error) {
  console.error('Task failed:', error.message);
}