diff --git a/src/lib.rs b/src/lib.rs
index 407a5df..f200340 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -100,11 +100,11 @@
 //! let parent = "Hello world";
 //! let left = TextWithCursors::new(
 //!     "Hello beautiful world".to_string(),
-//!     vec![CursorPosition { id: 1, char_index: 6 }] // After "Hello "
+//!     vec![CursorPosition::new(1, 6)] // After "Hello "
 //! );
 //! let right = TextWithCursors::new(
 //!     "Hi world".to_string(),
-//!     vec![CursorPosition { id: 2, char_index: 0 }] // At the beginning
+//!     vec![CursorPosition::new(2, 0)] // At the beginning
 //! );
 //!
 //! let result = reconcile(parent, &left, &right, &*BuiltinTokenizer::Word);
@@ -173,7 +173,7 @@
 //!     &changes.into()
 //! );
 //!
-//! let serialized = serde_yaml::to_string(&result.to_diff()).unwrap();
+//! let serialized = serde_yaml::to_string(&result.to_diff().unwrap()).unwrap();
 //! assert_eq!(
 //!     serialized,
 //!     concat!(
diff --git a/src/operation_transformation.rs b/src/operation_transformation.rs
index 36803e9..bbaf73e 100644
--- a/src/operation_transformation.rs
+++ b/src/operation_transformation.rs
@@ -156,7 +156,7 @@ mod test {
                     .unwrap()
                     .chars()
                     .skip(range.start)
-                    .take(range.end)
+                    .take(range.len())
                     .collect::<String>()
             })
             .collect::<Vec<_>>();
diff --git a/src/operation_transformation/diff_error.rs b/src/operation_transformation/diff_error.rs
index d10065f..22e717f 100644
--- a/src/operation_transformation/diff_error.rs
+++ b/src/operation_transformation/diff_error.rs
@@ -16,4 +16,11 @@ pub enum DiffError {
         /// The number of characters available from the position
         available: usize,
     },
+
+    /// A character count was too large to represent as i64
+    #[error("Integer overflow: value {value} cannot be represented as i64")]
+    IntegerOverflow {
+        /// The value that caused the overflow
+        value: usize,
+    },
 }
diff --git a/src/raw_operation.rs b/src/raw_operation.rs
index 1572e88..bde18c9 100644
--- a/src/raw_operation.rs
+++ b/src/raw_operation.rs
@@ -22,7 +22,7 @@ where
 {
     pub fn vec_from(left: &[Token<T>], right: &[Token<T>]) -> Vec<Self> { myers_diff(left, right) }
 
-    pub fn tokens(&self) -> &Vec<Token<T>> {
+    pub fn tokens(&self) -> &[Token<T>] {
         match self {
             RawOperation::Insert(tokens)
             | RawOperation::Delete(tokens)
@@ -34,7 +34,9 @@ where
         self.tokens().iter().map(Token::get_original_length).sum()
     }
 
-    pub fn get_original_text(self) -> String { self.tokens().iter().map(Token::original).collect() }
+    pub fn get_original_text(&self) -> String {
+        self.tokens().iter().map(Token::original).collect()
+    }
 
     pub fn is_left_joinable(&self) -> bool {
         let first_token = self.tokens().first();
diff --git a/src/tokenizer.rs b/src/tokenizer.rs
index 18b3e8a..4507c9a 100644
--- a/src/tokenizer.rs
+++ b/src/tokenizer.rs
@@ -1,5 +1,6 @@
 mod character_tokenizer;
 mod line_tokenizer;
+mod markdown_tokenizer;
 mod word_tokenizer;
 
 use std::ops::Deref;
@@ -22,6 +23,7 @@ pub type Tokenizer<T> = dyn Fn(&str) -> Vec<Token<T>>;
 pub enum BuiltinTokenizer {
     Character = "Character",
     Line = "Line",
+    Markdown = "Markdown",
     Word = "Word",
 }
 
@@ -31,6 +33,7 @@ pub enum BuiltinTokenizer {
 pub enum BuiltinTokenizer {
     Character,
     Line,
+    Markdown,
     Word,
 }
 
@@ -41,6 +44,7 @@ impl Deref for BuiltinTokenizer {
         match self {
             BuiltinTokenizer::Character => &character_tokenizer::character_tokenizer,
             BuiltinTokenizer::Line => &line_tokenizer::line_tokenizer,
+            BuiltinTokenizer::Markdown => &markdown_tokenizer::markdown_tokenizer,
             BuiltinTokenizer::Word => &word_tokenizer::word_tokenizer,
             #[cfg(feature = "wasm")]
             BuiltinTokenizer::__Invalid => panic!("Unexpected tokenizer type"),
diff --git a/src/types/cursor_position.rs b/src/types/cursor_position.rs
index 0a817a5..d69a1b2 100644
--- a/src/types/cursor_position.rs
+++ b/src/types/cursor_position.rs
@@ -10,8 +10,8 @@ use wasm_bindgen::prelude::*;
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[derive(Debug, Clone, PartialEq, Default)]
 pub struct CursorPosition {
-    pub id: usize,
-    pub char_index: usize,
+    pub(crate) id: usize,
+    pub(crate) char_index: usize,
 }
 
 #[cfg_attr(feature = "wasm", wasm_bindgen)]
diff --git a/src/types/text_with_cursors.rs b/src/types/text_with_cursors.rs
index 8f4af19..f58a34e 100644
--- a/src/types/text_with_cursors.rs
+++ b/src/types/text_with_cursors.rs
@@ -39,6 +39,11 @@ impl TextWithCursors {
     pub fn cursors(&self) -> Vec<CursorPosition> { self.cursors.clone() }
 }
 
+impl TextWithCursors {
+    #[must_use]
+    pub fn text_ref(&self) -> &str { &self.text }
+}
+
 impl<'a> From<&'a str> for TextWithCursors {
     fn from(text: &'a str) -> Self {
         Self {
diff --git a/src/utils/myers_diff.rs b/src/utils/myers_diff.rs
index de7c419..dd9f961 100644
--- a/src/utils/myers_diff.rs
+++ b/src/utils/myers_diff.rs
@@ -90,7 +90,7 @@ impl V {
         let offset = isize::try_from(max_d).expect("max_d must fit in isize");
         Self {
             offset,
-            v: vec![0; 2 * max_d],
+            v: vec![0; 2 * max_d + 1],
         }
     }
 
diff --git a/src/utils/string_builder.rs b/src/utils/string_builder.rs
index fd89d63..abe372c 100644
--- a/src/utils/string_builder.rs
+++ b/src/utils/string_builder.rs
@@ -1,10 +1,10 @@
-use std::{fmt, iter::Iterator};
+use std::{fmt, str::Chars};
 
 /// A helper for building a string sequentially from an original string via
 /// insertions, deletions, and copies. All operations use character counts,
 /// safe for UTF-8. Methods must be called in-order.
 pub struct StringBuilder<'a> {
-    original: Box<dyn Iterator<Item = char> + 'a>,
+    original: Chars<'a>,
     buffer: String,
 
     #[cfg(debug_assertions)]
@@ -26,7 +26,7 @@ impl fmt::Debug for StringBuilder<'_> {
 impl StringBuilder<'_> {
     pub fn new(original: &str) -> StringBuilder<'_> {
         StringBuilder {
-            original: Box::new(original.chars()),
+            original: original.chars(),
             buffer: String::with_capacity(original.len()),
 
             #[cfg(debug_assertions)]
diff --git a/src/wasm.rs b/src/wasm.rs
index 17dc7d5..c15a97f 100644
--- a/src/wasm.rs
+++ b/src/wasm.rs
@@ -5,9 +5,6 @@ use wasm_bindgen::prelude::*;
 
 use crate::{BuiltinTokenizer, CursorPosition, EditedText, SpanWithHistory, TextWithCursors};
 
-#[global_allocator]
-static ALLOC: wee_alloc::WeeAlloc<'_> = wee_alloc::WeeAlloc::INIT;
-
 /// WASM wrapper around `crate::reconcile` for merging text
 #[wasm_bindgen(js_name = reconcile)]
 #[must_use]
@@ -34,11 +31,11 @@ pub fn reconcile_with_history(
     set_panic_hook();
 
     let reconciled = crate::reconcile(parent, left, right, &*tokenizer);
-    let text_with_cursors = reconciled.apply();
+    let (text_with_cursors, history) = reconciled.apply_with_all();
 
     TextWithCursorsAndHistory {
         text_with_cursors,
-        history: reconciled.apply_with_history(),
+        history,
     }
 }
 
@@ -81,17 +78,23 @@ pub fn generic_reconcile(
 
 /// WASM wrapper around getting a compact diff representation of two texts as a
 /// list of numbers and strings
+///
+/// # Errors
+///
+/// Returns a JS error if integer overflow occurs during diff computation.
 #[wasm_bindgen(js_name = diff)]
-#[must_use]
-pub fn diff(parent: &str, changed: &TextWithCursors, tokenizer: BuiltinTokenizer) -> Vec<JsValue> {
+pub fn diff(
+    parent: &str,
+    changed: &TextWithCursors,
+    tokenizer: BuiltinTokenizer,
+) -> Result<Vec<JsValue>, JsValue> {
     set_panic_hook();
 
     let edited_text = EditedText::from_strings_with_tokenizer(parent, changed, &*tokenizer);
     edited_text
         .to_diff()
-        .into_iter()
-        .map(std::convert::Into::into)
-        .collect()
+        .map(|diff| diff.into_iter().map(std::convert::Into::into).collect())
+        .map_err(|e| JsValue::from_str(&e.to_string()))
 }
 
 /// Inverse of `diff`, applies a compact diff representation to a parent text
diff --git a/tests/example_document.rs b/tests/example_document.rs
index 2984077..6d8f370 100644
--- a/tests/example_document.rs
+++ b/tests/example_document.rs
@@ -65,9 +65,9 @@ impl ExampleDocument {
         let mut result = merged.text();
         for (i, cursor) in merged.cursors().iter().enumerate() {
             assert!(
-                cursor.char_index <= result.len(), // equals in case of insert at the end
+                cursor.char_index() <= result.len(), // equals in case of insert at the end
                 "Cursor index out of bounds: {} > {} when testing for '{}.'",
-                cursor.char_index,
+                cursor.char_index(),
                 result.len(),
                 result
             );
@@ -75,7 +75,7 @@ impl ExampleDocument {
             result.insert(
                 result
                     .char_indices()
-                    .nth(cursor.char_index + i)
+                    .nth(cursor.char_index() + i)
                     .map_or_else(|| result.len(), |(byte_index, _)| byte_index), /* find the utf8 char index of the insert
                                                                                   * in byte index */
                 '|',
@@ -94,10 +94,7 @@ impl ExampleDocument {
         let mut cursors = Vec::new();
         for (i, c) in text.chars().enumerate() {
             if c == '|' {
-                cursors.push(CursorPosition {
-                    id: 0,
-                    char_index: i - cursors.len(),
-                });
+                cursors.push(CursorPosition::new(0, i - cursors.len()));
             }
         }
         cursors
diff --git a/tests/test.rs b/tests/test.rs
index 2e54e6c..68d8762 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -49,12 +49,14 @@ fn test_document_one_way_with_serialisation() {
             &*BuiltinTokenizer::Word,
         );
 
-        let serialised_left =
-            serde_yaml::from_str(&serde_yaml::to_string(&left_operations.to_diff()).unwrap())
-                .unwrap();
-        let serialised_right =
-            serde_yaml::from_str(&serde_yaml::to_string(&right_operations.to_diff()).unwrap())
-                .unwrap();
+        let serialised_left = serde_yaml::from_str(
+            &serde_yaml::to_string(&left_operations.to_diff().unwrap()).unwrap(),
+        )
+        .unwrap();
+        let serialised_right = serde_yaml::from_str(
+            &serde_yaml::to_string(&right_operations.to_diff().unwrap()).unwrap(),
+        )
+        .unwrap();
 
         let restored_left_operations =
             EditedText::from_diff(&parent, serialised_left, &*BuiltinTokenizer::Word).unwrap();
diff --git a/tests/wasm.rs b/tests/wasm.rs
index 304ee6e..82af503 100644
--- a/tests/wasm.rs
+++ b/tests/wasm.rs
@@ -60,7 +60,7 @@ fn test_diff() {
     let parent = "hello ";
     let changed = "world";
 
-    let result = diff(parent, &changed.into(), BuiltinTokenizer::Word);
+    let result = diff(parent, &changed.into(), BuiltinTokenizer::Word).unwrap();
 
     assert_eq!(result.len(), 2);
     let first: i64 = result[0].clone().try_into().unwrap();