new identity.has() API

lib/index.js

@@ -385,6 +385,30 @@ function initDB(peer, config) {
     cb(err)
   }
 
+  /**
+   * @param {{
+   *   keypair?: KeypairPublicSlice;
+   *   identity: string;
+   * }} opts
+   */
+  function identityHas(opts) {
+    const keypair = opts?.keypair ?? config.keypair
+
+    const identityTangle = new DBTangle(opts.identity, records())
+    for (const msgHash of identityTangle.topoSort()) {
+      const msg = get(msgHash)
+      if (!msg?.data) continue
+      /** @type {IdentityData} */
+      const data = msg.data
+      if (data.action !== 'add') continue
+      if (data.add.key.algorithm !== keypair.curve) continue
+      if (data.add.key.bytes === keypair.public) {
+        return true
+      }
+    }
+    return false
+  }
+
   /**
    * @param {{
    *   keypair?: Keypair,
@@ -722,6 +746,7 @@ function initDB(peer, config) {
       findOrCreate: findOrCreateIdentity,
       add: addToIdentity,
       consent: consentToIdentity,
+      has: identityHas,
     },
     feed: {
       publish: publishToFeed,

test/identity-add.test.js

@@ -26,6 +26,8 @@ test('identity.add()', async (t) => {
     domain: 'person',
   })
 
+  assert.equal(peer.db.identity.has({ identity: id, keypair: keypair2 }), false)
+
   const consent = peer.db.identity.consent({ identity: id, keypair: keypair2 })
 
   const identityRec1 = await p(peer.db.identity.add)({
@@ -60,6 +62,8 @@ test('identity.add()', async (t) => {
   )
   assert.equal(msg.pubkey, keypair1.public, 'msg.pubkey OLD KEY')
 
+  assert.equal(peer.db.identity.has({ identity: id, keypair: keypair2 }), true)
+
   await p(peer.close)()
 })