feat: ensure collection links are sorted with root as the first link

src/commands/stac-github-import/__test__/stac.link.test.ts

@@ -0,0 +1,112 @@
+import { describe, it } from 'node:test';
+import { sortLinks } from '../stac.github.import.js';
+import assert from 'node:assert';
+
+function shuffle<T>(array: T[]): T[] {
+  let currentIndex = array.length;
+  let randomIndex;
+
+  // While there remain elements to shuffle.
+  while (currentIndex !== 0) {
+    // Pick a remaining element.
+    randomIndex = Math.floor(Math.random() * currentIndex);
+    currentIndex--;
+
+    // And swap it with the current element.
+    const randomItem = array[randomIndex] as T;
+    const currentItem = array[currentIndex] as T;
+    array[currentIndex] = randomItem;
+    array[randomIndex] = currentItem;
+  }
+
+  return array;
+}
+
+describe('sortLinks', () => {
+  it('should make root first', () => {
+    const links = [
+      { rel: 'self', href: './collection.json', type: 'application/json' },
+      { rel: 'item', href: './AY30_1000_4643.json', type: 'application/json' },
+      { rel: 'item', href: './AY30_1000_4844.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_2932.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_4750.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_4807.json', type: 'application/json' },
+      {
+        rel: 'root',
+        href: 'https://linz-imagery.s3.ap-southeast-2.amazonaws.com/catalog.json',
+        type: 'application/json',
+      },
+      { rel: 'item', href: './AY31_1000_4809.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_4808.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_2934.json', type: 'application/json' },
+      { rel: 'item', href: './AY30_1000_4744.json', type: 'application/json' },
+    ];
+    sortLinks(links);
+    assert.equal(links[0]?.rel, 'root');
+  });
+
+  it('should sort alphabetically the items', () => {
+    const links = [
+      { rel: 'self', href: './collection.json', type: 'application/json' },
+      { rel: 'item', href: './AY30_1000_4643.json', type: 'application/json' },
+      { rel: 'item', href: './AY30_1000_4844.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_2932.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_4750.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_4807.json', type: 'application/json' },
+      {
+        rel: 'root',
+        href: 'https://linz-imagery.s3.ap-southeast-2.amazonaws.com/catalog.json',
+        type: 'application/json',
+      },
+      { rel: 'item', href: './AY31_1000_4809.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_4808.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_2934.json', type: 'application/json' },
+      { rel: 'item', href: './AY30_1000_4744.json', type: 'application/json' },
+    ];
+    sortLinks(links);
+    const items = links.filter((f) => f.rel === 'item').map((f) => f.href);
+    assert.deepEqual(items, [
+      './AY30_1000_4643.json',
+      './AY30_1000_4744.json',
+      './AY30_1000_4844.json',
+      './AY31_1000_2932.json',
+      './AY31_1000_2934.json',
+      './AY31_1000_4750.json',
+      './AY31_1000_4807.json',
+      './AY31_1000_4808.json',
+      './AY31_1000_4809.json',
+    ]);
+  });
+
+  it('should be stable', () => {
+    const links = [
+      { rel: 'self', href: './collection.json', type: 'application/json' },
+      { rel: 'test', href: './AY30_1000_4643.json', type: 'application/json' },
+      { rel: 'item', href: './AY30_100_4844.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_2932.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_10_4750.json', type: 'application/json' },
+      { rel: 'item', href: './AY31_1000_4807.json', type: 'application/json' },
+      {
+        rel: 'root',
+        href: 'https://linz-imagery.s3.ap-southeast-2.amazonaws.com/catalog.json',
+        type: 'application/json',
+      },
+      { rel: 'self', href: './AY31_500_4809.json', type: 'application/json' },
+      { rel: 'item', href: './AY32_1000_4808.json', type: 'application/json' },
+      { rel: 'root', href: 'https://AZ31_1000_2934.json', type: 'application/json' },
+      { rel: 'fake', href: './AY30_1000_4744.json', type: 'application/json' },
+    ];
+
+    sortLinks(links);
+    const sorted = links.map((f) => f.href);
+
+    for (let i = 0; i < 1000; i++) {
+      const shuffled = shuffle(links);
+      sortLinks(shuffled);
+      assert.deepEqual(
+        shuffled.map((f) => f.href),
+        sorted,
+      );
+    }
+  });
+});

src/commands/stac-github-import/stac.github.import.ts

@@ -68,6 +68,8 @@ export const commandStacGithubImport = command({
 
     logger.info({ href: selfLink.href }, 'Stac:SetRoot');
 
+    sortLinks(collection.links);
+
     // Update the root link in the collection to the one defined in the repo template
     const rootLink = collection.links.find((f) => f.rel === 'root');
     if (rootLink) {
@@ -97,3 +99,22 @@ export const commandStacGithubImport = command({
     execFileSync('git', ['push', 'origin', 'HEAD', '--force'], { cwd: gitRepo });
   },
 });
+
+/** All other rel's are set between "root" and "item" */
+const RelPriorityDefault = 50;
+/** Ensure root rel are put before everything else */
+const RelPriority: Record<string, number> = {
+  root: 0,
+  item: 100,
+};
+
+/** Sort collection links keeping non items at the top then items sorted by href */
+export function sortLinks(links: st.StacLink[]): void {
+  links.sort((a, b) => {
+    if (a.rel === b.rel) return a.href.localeCompare(b.href);
+    const aRel = RelPriority[a.rel] ?? RelPriorityDefault;
+    const bRel = RelPriority[b.rel] ?? RelPriorityDefault;
+    if (aRel === bRel) return a.href.localeCompare(b.href);
+    return aRel - bRel;
+  });
+}