From 39f853fc4a67e0714fde68c726651535a6f08ca9 Mon Sep 17 00:00:00 2001
From: Kata Martin <katasm@gmail.com>
Date: Thu, 9 Dec 2021 16:54:10 -0800
Subject: [PATCH 1/2] Inspect datasets array instead of using kwargs

---
 src/utils.js | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/utils.js b/src/utils.js
index faf51ae..1bc5d19 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -249,12 +249,10 @@ export const getTilesOfRegion = (region, level) => {
 }
 
 export const getPyramidMetadata = (metadata) => {
-  const kwargs = metadata.metadata['.zattrs'].multiscales[0].metadata.kwargs
-  const maxZoom = kwargs.levels - 1
-  const levels = Array(maxZoom + 1)
-    .fill()
-    .map((_, i) => i)
-  const tileSize = kwargs.pixels_per_tile
+  const datasets = metadata.metadata['.zattrs'].multiscales[0].datasets
+  const levels = datasets.map((dataset) => Number(dataset.path))
+  const maxZoom = Math.max(...levels)
+  const tileSize = datasets[0].pixels_per_tile
   return { levels, maxZoom, tileSize }
 }
 

From 686012f728a1a379cd11812089f1902d53796535 Mon Sep 17 00:00:00 2001
From: Kata Martin <katasm@gmail.com>
Date: Fri, 10 Dec 2021 16:53:08 -0800
Subject: [PATCH 2/2] Throw errors for breadcrumbs in metadata getter

---
 src/utils.js | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/utils.js b/src/utils.js
index 1bc5d19..222ad78 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -249,10 +249,31 @@ export const getTilesOfRegion = (region, level) => {
 }
 
 export const getPyramidMetadata = (metadata) => {
-  const datasets = metadata.metadata['.zattrs'].multiscales[0].datasets
+  const multiscales = metadata.metadata['.zattrs'].multiscales
+
+  if (!multiscales) {
+    throw new Error(
+      'Missing `multiscales` value in .zattrs. Please check your pyramid generation code.'
+    )
+  }
+
+  const datasets = multiscales[0].datasets
+
+  if (!datasets || datasets.length === 0) {
+    throw new Error(
+      'No datasets provided in `multiscales` metadata. Please check your pyramid generation code.'
+    )
+  }
+
   const levels = datasets.map((dataset) => Number(dataset.path))
   const maxZoom = Math.max(...levels)
   const tileSize = datasets[0].pixels_per_tile
+
+  if (!tileSize) {
+    throw new Error(
+      'Missing required `pixels_per_tile` value in `multiscales` metadata. Please check your pyramid generation code.'
+    )
+  }
   return { levels, maxZoom, tileSize }
 }