diff --git a/src/coordinates-of.js b/src/coordinates-of.js
index f125948..f8d936b 100644
--- a/src/coordinates-of.js
+++ b/src/coordinates-of.js
@@ -24,9 +24,9 @@ export function coordinatesOf(source, parsedResult) {
 
   let { contentRange: byteRange } = parsedResult;
   let inclusiveContent = buffer
-    .slice(byteRange.startByte, byteRange.endByte)
+    .subarray(byteRange.startByte, byteRange.endByte)
     .toString();
-  let beforeContent = buffer.slice(0, byteRange.startByte).toString();
+  let beforeContent = buffer.subarray(0, byteRange.startByte).toString();
   let before = beforeContent.length;
 
   let startCharIndex = before;
diff --git a/src/transformer.js b/src/transformer.js
index 05ff87e..3094c4f 100644
--- a/src/transformer.js
+++ b/src/transformer.js
@@ -414,7 +414,7 @@ export class ParseResultStringUtils {
    * @param {ParseResult} parseResult
    */
   contentBefore(parseResult) {
-    return this.#buffer.slice(0, parseResult.range.startByte).toString();
+    return this.#buffer.subarray(0, parseResult.range.startByte).toString();
   }
 
   /**
@@ -422,7 +422,7 @@ export class ParseResultStringUtils {
    */
   originalContentOf(parseResult) {
     return this.#buffer
-      .slice(
+      .subarray(
         parseResult.contentRange.startByte,
         parseResult.contentRange.endByte,
       )
@@ -445,7 +445,10 @@ export class ParseResultStringUtils {
    */
   openingTag(parseResult) {
     let openingTag = this.#buffer
-      .slice(parseResult.startRange.startByte, parseResult.startRange.endByte)
+      .subarray(
+        parseResult.startRange.startByte,
+        parseResult.startRange.endByte,
+      )
       .toString();
     return openingTag;
   }
@@ -455,7 +458,7 @@ export class ParseResultStringUtils {
    */
   closingTag(parseResult) {
     let closingTag = this.#buffer
-      .slice(parseResult.endRange.startByte, parseResult.endRange.endByte)
+      .subarray(parseResult.endRange.startByte, parseResult.endRange.endByte)
       .toString();
     return closingTag;
   }