From 4b35de5ad518619ae7e2d46b201dbd3cdafa782b Mon Sep 17 00:00:00 2001
From: Will Hawker <will.hawker@nextapp.co>
Date: Tue, 8 Jun 2021 21:09:44 +0100
Subject: [PATCH] add clear to YMap to remove all elements

---
 README.md            |  2 ++
 src/types/YMap.js    | 16 +++++++++++
 tests/y-map.tests.js | 67 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 85 insertions(+)

diff --git a/README.md b/README.md
index 5fb44e08..cc1c5136 100644
--- a/README.md
+++ b/README.md
@@ -334,6 +334,8 @@ or any of its children.
     <dd></dd>
     <b><code>get(index:number)</code></b>
     <dd></dd>
+    <b><code>clear()</code></b>
+    <dd>Removes all elements from this YMap.</dd>
     <b><code>clone():Y.Map</code></b>
     <dd>Clone this type into a fresh Yjs type.</dd>
     <b><code>toJSON():Object&lt;string, Object|boolean|Array|string|number|Uint8Array&gt;</code></b>
diff --git a/src/types/YMap.js b/src/types/YMap.js
index 6cb1b309..351220a2 100644
--- a/src/types/YMap.js
+++ b/src/types/YMap.js
@@ -237,6 +237,22 @@ export class YMap extends AbstractType {
     return typeMapHas(this, key)
   }
 
+  /**
+   * Removes all elements from this YMap.
+   */
+  clear () {
+    if (this.doc !== null) {
+      transact(this.doc, transaction => {
+        this.forEach(function (value, key, map) {
+          console.log('deleting', key)
+          typeMapDelete(transaction, map, key)
+        })
+      })
+    } else {
+      /** @type {Map<string, any>} */ (this._prelimContent).clear()
+    }
+  }
+
   /**
    * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    */
diff --git a/tests/y-map.tests.js b/tests/y-map.tests.js
index 9ac259ab..7cbca52f 100644
--- a/tests/y-map.tests.js
+++ b/tests/y-map.tests.js
@@ -189,6 +189,49 @@ export const testGetAndSetAndDeleteOfMapProperty = tc => {
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSetAndClearOfMapProperties = tc => {
+  const { testConnector, users, map0 } = init(tc, { users: 1 })
+  map0.set('stuff', 'c0')
+  map0.set('otherstuff', 'c1')
+  map0.clear()
+  testConnector.flushAllMessages()
+  for (const user of users) {
+    const u = user.getMap('map')
+    t.assert(u.get('stuff') === undefined)
+    t.assert(u.get('otherstuff') === undefined)
+    t.assert(u.size === 0, `map size after clear is ${u.size}, expected 0`)
+  }
+  compare(users)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSetAndClearOfMapPropertiesWithConflicts = tc => {
+  const { testConnector, users, map0, map1, map2, map3 } = init(tc, { users: 4 })
+  map0.set('stuff', 'c0')
+  map1.set('stuff', 'c1')
+  map1.set('stuff', 'c2')
+  map2.set('stuff', 'c3')
+  testConnector.flushAllMessages()
+  map0.set('otherstuff', 'c0')
+  map1.set('otherstuff', 'c1')
+  map2.set('otherstuff', 'c2')
+  map3.set('otherstuff', 'c3')
+  map3.clear()
+  testConnector.flushAllMessages()
+  for (const user of users) {
+    const u = user.getMap('map')
+    t.assert(u.get('stuff') === undefined)
+    t.assert(u.get('otherstuff') === undefined)
+    t.assert(u.size === 0, `map size after clear is ${u.size}, expected 0`)
+  }
+  compare(users)
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -335,6 +378,30 @@ export const testThrowsAddAndUpdateAndDeleteEvents = tc => {
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testThrowsDeleteEventsOnClear = tc => {
+  const { users, map0 } = init(tc, { users: 2 })
+  /**
+   * @type {Object<string,any>}
+   */
+  let event = {}
+  map0.observe(e => {
+    event = e // just put it on event, should be thrown synchronously anyway
+  })
+  // set values
+  map0.set('stuff', 4)
+  map0.set('otherstuff', new Y.Array())
+  // clear
+  map0.clear()
+  compareEvent(event, {
+    keysChanged: new Set(['stuff', 'otherstuff']),
+    target: map0
+  })
+  compare(users)
+}
+
 /**
  * @param {t.TestCase} tc
  */