Add code sample showing how to walk an owner directory

_code-samples/walk-owner-directory/js/iterate-owner-directory.js

@@ -0,0 +1,55 @@
+// iterate-owner-directory.js
+// Iterate over an account's owner directory and display how many ledger entries
+// are in each page. In cases of highly active accounts, it can demonstrate
+// the extent of "fragmentation" with skipped page numbers and non-full pages.
+
+import xrpl from 'xrpl'
+
+const client = new xrpl.Client('wss://s.altnet.rippletest.net:51233')
+await client.connect()
+
+const owner = "rPT1Sjq2YGrBMTttX4GZHjKu9dyfzbpAYe" // Testnet faucet
+// const owner = "rP9jPyP5kyvFRb6ZiRghAGw5u8SGAmU4bd" // TST issuer
+
+// Set initial values for iterating
+let sub_index = 0 // Directory root
+let ledger_index = "validated"
+
+// Query pages from the owner directory until they run out
+console.log("Page #\t\t\tEntry count")
+console.log("-----------------------------------")
+while (true) {
+    // console.log(`Getting directory page ${sub_index}`)
+    const resp = await client.request({
+        "command": "ledger_entry",
+        "directory": {
+            "owner": owner,
+            "sub_index": sub_index
+        },
+        "ledger_index": ledger_index
+    })
+    if (resp.error) {
+        console.error("ledger_entry failed with error",resp.error)
+        break
+    }
+
+    // Consistently iterate the same ledger: query by index after the first
+    if (ledger_index === "validated") {
+        ledger_index = resp.result.ledger_index
+    }
+
+    console.log(`${sub_index}\t\t\t${resp.result.node.Indexes.length}`)
+    // console.log(`This page contains ${resp.result.node.Indexes.length} items.`)
+
+    // Continue onto another page if this one has more
+    if (resp.result.node.hasOwnProperty("IndexNext")) {
+        // The directory continues onto another page.
+        // IndexNext is returned as hex but sub_index needs decimal
+        sub_index = parseInt(resp.result.node.IndexNext, 16)
+    } else {
+        console.info("This is the last page of the directory")
+        break
+    }
+}
+
+client.disconnect()