fix: add non-null assertions for noUncheckedIndexedAccess compliance

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

Author: cmdcolin

src/bgzFilehandle.ts

@@ -55,10 +55,10 @@ export default class BgzFilehandle {
       blockNum += 1
     ) {
       const uncompressedBuffer = await this._readAndUncompressBlock(
-        blockPositions[blockNum][0],
-        blockPositions[blockNum + 1][0],
+        blockPositions[blockNum]![0],
+        blockPositions[blockNum + 1]![0],
       )
-      const [, uncompressedPosition] = blockPositions[blockNum]
+      const [, uncompressedPosition] = blockPositions[blockNum]!
       const sourceOffset =
         uncompressedPosition >= position ? 0 : position - uncompressedPosition
       const sourceEnd =

src/gziIndex.ts

@@ -85,15 +85,15 @@ export default class GziIndex {
       return []
     }
     const entries = await this._getIndex()
-    const relevant = []
+    const relevant: ([number, number] | never[])[] = []
 
     let lowerBound = 0
     let upperBound = entries.length - 1
     let searchPosition = Math.floor(entries.length / 2)
 
     let comparison = compare(
       position,
-      entries[searchPosition],
+      entries[searchPosition]!,
       entries[searchPosition + 1],
     )
     while (comparison !== 0) {
@@ -105,17 +105,17 @@ export default class GziIndex {
       searchPosition = Math.ceil((upperBound - lowerBound) / 2) + lowerBound
       comparison = compare(
         position,
-        entries[searchPosition],
+        entries[searchPosition]!,
         entries[searchPosition + 1],
       )
     }
 
     // here's where we read forward
-    relevant.push(entries[searchPosition])
+    relevant.push(entries[searchPosition]!)
     let i = searchPosition + 1
     for (; i < entries.length; i += 1) {
-      relevant.push(entries[i])
-      if (entries[i][UNCOMPRESSED_POSITION] >= endPosition) {
+      relevant.push(entries[i]!)
+      if (entries[i]![UNCOMPRESSED_POSITION] >= endPosition) {
         break
       }
     }

src/long.ts

@@ -3,14 +3,14 @@ const TWO_PWR_32_DBL = TWO_PWR_16_DBL * TWO_PWR_16_DBL
 
 export function longFromBytesToUnsigned(source: Uint8Array, i = 0) {
   const low =
-    source[i] |
-    (source[i + 1] << 8) |
-    (source[i + 2] << 16) |
-    (source[i + 3] << 24)
+    source[i]! |
+    (source[i + 1]! << 8) |
+    (source[i + 2]! << 16) |
+    (source[i + 3]! << 24)
   const high =
-    source[i + 4] |
-    (source[i + 5] << 8) |
-    (source[i + 6] << 16) |
-    (source[i + 7] << 24)
+    source[i + 4]! |
+    (source[i + 5]! << 8) |
+    (source[i + 6]! << 16) |
+    (source[i + 7]! << 24)
   return (high >>> 0) * TWO_PWR_32_DBL + (low >>> 0)
 }