CesiumJS Core Utilities

---
name: cesiumjs-core-utilities
description: "CesiumJS core utilities and networking - Resource, Color, Event, Request, RequestScheduler, error handling, helper functions, feature detection. Use when fetching remote data, managing HTTP requests, working with colors, handling events, debugging errors, or using utility functions like defined, clone, or buildModuleUrl."
---
# CesiumJS Core Utilities & Networking

Version baseline: CesiumJS v1.142+ (ES module imports, `defaultValue` removed in v1.134)

## Breaking Change: defaultValue Removed (v1.134)

```js
// WRONG (removed in v1.134)
const name = defaultValue(options.name, "default");
const opts = defaultValue(options, defaultValue.EMPTY_OBJECT);

// CORRECT (v1.134+)
import { Frozen } from "cesium";
const name = options.name ?? "default";
const opts = options ?? Frozen.EMPTY_OBJECT;
```

`Frozen.EMPTY_OBJECT` is `Object.freeze({})` and `Frozen.EMPTY_ARRAY` is `Object.freeze([])`. Use them as safe defaults for options objects and array parameters.

## Resource: HTTP Requests and Data Fetching