feat: add clear methods (#478)

* feat: add clear method

* feat: expose clear fn to wasm and rust

crates/loro-internal/src/handler.rs

@@ -11,7 +11,7 @@ use crate::{
     diff::{myers_diff, OperateProxy},
     event::{Diff, TextDiffItem},
     op::ListSlice,
-    state::{ContainerState, IndexType, State, TreeParentId},
+    state::{IndexType, State, TreeParentId},
     txn::EventHint,
     utils::{string_slice::StringSlice, utf16::count_utf16_len},
 };
@@ -777,6 +777,7 @@ impl HandlerTrait for ListHandler {
         }
     }
 }
+
 #[derive(Clone)]
 pub struct UnknownHandler {
     inner: BasicHandler,
@@ -2690,6 +2691,21 @@ impl ListHandler {
             MaybeDetached::Attached(a) => a.is_deleted(),
         }
     }
+
+    pub fn clear(&self) -> LoroResult<()> {
+        match &self.inner {
+            MaybeDetached::Detached(l) => {
+                let mut l = l.try_lock().unwrap();
+                l.value.clear();
+                Ok(())
+            }
+            MaybeDetached::Attached(a) => a.with_txn(|txn| self.clear_with_txn(txn)),
+        }
+    }
+
+    pub fn clear_with_txn(&self, txn: &mut Transaction) -> LoroResult<()> {
+        self.delete_with_txn(txn, 0, self.len())
+    }
 }
 
 impl MovableListHandler {
@@ -3207,8 +3223,8 @@ impl MovableListHandler {
                 let a = state.as_movable_list_state().unwrap();
                 match a.get(index, IndexType::ForUser) {
                     Some(v) => {
-                        if let LoroValue::Container(id) = v {
-                            Some(ValueOrHandler::Handler(create_handler(m, id.clone())))
+                        if let LoroValue::Container(c) = v {
+                            Some(ValueOrHandler::Handler(create_handler(m, c.clone())))
                         } else {
                             Some(ValueOrHandler::Value(v.clone()))
                         }
@@ -3329,6 +3345,21 @@ impl MovableListHandler {
             MaybeDetached::Attached(a) => a.is_deleted(),
         }
     }
+
+    pub fn clear(&self) -> LoroResult<()> {
+        match &self.inner {
+            MaybeDetached::Detached(d) => {
+                let mut d = d.lock().unwrap();
+                d.value.clear();
+                Ok(())
+            }
+            MaybeDetached::Attached(a) => a.with_txn(|txn| self.clear_with_txn(txn)),
+        }
+    }
+
+    pub fn clear_with_txn(&self, txn: &mut Transaction) -> LoroResult<()> {
+        self.delete_with_txn(txn, 0, self.len())
+    }
 }
 
 impl MapHandler {
@@ -3638,6 +3669,34 @@ impl MapHandler {
             MaybeDetached::Attached(a) => a.is_deleted(),
         }
     }
+
+    pub fn clear(&self) -> LoroResult<()> {
+        match &self.inner {
+            MaybeDetached::Detached(m) => {
+                let mut m = m.try_lock().unwrap();
+                m.value.clear();
+                Ok(())
+            }
+            MaybeDetached::Attached(a) => a.with_txn(|txn| self.clear_with_txn(txn)),
+        }
+    }
+
+    pub fn clear_with_txn(&self, txn: &mut Transaction) -> LoroResult<()> {
+        let keys: Vec<InternalString> = self.inner.try_attached_state()?.with_state(|state| {
+            state
+                .as_map_state()
+                .unwrap()
+                .iter()
+                .map(|(k, _)| k.clone())
+                .collect()
+        });
+
+        for key in keys {
+            self.delete_with_txn(txn, &key)?;
+        }
+
+        Ok(())
+    }
 }
 
 #[inline(always)]

crates/loro-wasm/src/lib.rs

@@ -2415,6 +2415,12 @@ impl LoroMap {
         };
         handler_to_js_value(Handler::Map(h), self.doc.clone()).into()
     }
+
+    /// Delete all key-value pairs in the map.
+    pub fn clear(&self) -> JsResult<()> {
+        self.handler.clear()?;
+        Ok(())
+    }
 }
 
 impl Default for LoroMap {
@@ -2743,6 +2749,12 @@ impl LoroList {
             Ok(None)
         }
     }
+
+    /// Delete all elements in the list.
+    pub fn clear(&self) -> JsResult<()> {
+        self.handler.clear()?;
+        Ok(())
+    }
 }
 
 impl Default for LoroList {
@@ -3115,6 +3127,12 @@ impl LoroMovableList {
             v.into()
         }))
     }
+
+    /// Delete all elements in the list.
+    pub fn clear(&self) -> JsResult<()> {
+        self.handler.clear()?;
+        Ok(())
+    }
 }
 
 /// The handler of a tree(forest) container.

crates/loro/src/lib.rs

@@ -1058,6 +1058,11 @@ impl LoroList {
     pub fn to_vec(&self) -> Vec<LoroValue> {
         Arc::unwrap_or_clone(self.get_value().into_list().unwrap())
     }
+
+    /// Delete all elements in the list.
+    pub fn clear(&self) -> LoroResult<()> {
+        self.handler.clear()
+    }
 }
 
 impl Default for LoroList {
@@ -1229,6 +1234,11 @@ impl LoroMap {
                 .get_or_create_container(key, child.to_handler())?,
         ))
     }
+
+    /// Delete all key-value pairs in the map.
+    pub fn clear(&self) -> LoroResult<()> {
+        self.handler.clear()
+    }
 }
 
 impl Default for LoroMap {
@@ -2102,6 +2112,11 @@ impl LoroMovableList {
     pub fn to_vec(&self) -> Vec<LoroValue> {
         Arc::unwrap_or_clone(self.get_value().into_list().unwrap())
     }
+
+    /// Delete all elements in the list.
+    pub fn clear(&self) -> LoroResult<()> {
+        self.handler.clear()
+    }
 }
 
 impl Default for LoroMovableList {