NativeScript/tests/app/ui/image-cache/image-cache-tests.ts

// >> image-cache-require
import * as imageCacheModule from "ui/image-cache";
import * as imageSource from "image-source";
import * as fs from "file-system";
// << image-cache-require

export function test_DummyTestForSnippetOnly() {
    // >> image-cache-request-images
    var cache = new imageCacheModule.Cache();
    cache.placeholder = imageSource.fromFile(fs.path.join(__dirname, "res/no-image.png"));
    cache.maxRequests = 5;
    
    // Enable download while not scrolling
    cache.enableDownload();
    
    var imgSouce: imageSource.ImageSource;
    var url = "https://github.com/NativeScript.png";
    // Try to read the image from the cache
    var image = cache.get(url);
    if (image) {
        // If present -- use it.
        imgSouce = imageSource.fromNativeSource(image);
    }
    else {
        // If not present -- request its download.
        cache.push({
            key: url,
            url: url,
            completed: (image: any, key: string) => {
                if (url === key) {
                    imgSouce = imageSource.fromNativeSource(image);
                }
            }
        });
    }

    // Disable download while scrolling
    cache.disableDownload();
    // << image-cache-request-images
}