feat: adding docs for payment metadata (#124)

Co-authored-by: vacwmX <vacwm01@gmail.com>
Co-authored-by: ok300 <106775972+ok300@users.noreply.github.com>

snippets/react-native/metadata.ts

@@ -0,0 +1,66 @@
+import { setPaymentMetadata, listPayments } from '@breeztech/react-native-breez-sdk'
+
+const testSetPaymentMetadata = async () => {
+  // ANCHOR: set-payment-metadata
+  await setPaymentMetadata('target-payment-hash', '{"myCustomValue":true}')
+  // ANCHOR_END: set-payment-metadata
+}
+
+const testFilterPaymentMetadata = async () => {
+  // ANCHOR: filter-payment-metadata
+  const metadataFilters = [
+    {
+      jsonPath: 'myCustomValue',
+      jsonValue: 'true'
+    }
+  ]
+
+  try {
+    await listPayments({
+      metadataFilters
+    })
+  } catch (err) {
+    // handle error
+  }
+  // ANCHOR_END: filter-payment-metadata
+}
+
+const testFilterPaymentMetadataString = async () => {
+  // ANCHOR: filter-payment-metadata-string
+  // Note: These are equivalent
+  const metadataFilters = [
+    {
+      jsonPath: 'customerName',
+      jsonValue: 'Satoshi Nakamoto'
+    },
+    {
+      jsonPath: 'customerName',
+      jsonValue: JSON.stringify('Satoshi Nakamoto')
+    }
+  ]
+  // ANCHOR_END: filter-payment-metadata-string
+}
+
+const testFilterPaymentMetadataObject = async () => {
+  // ANCHOR: filter-payment-metadata-object
+  // This will *NOT* work
+  const _metadataFilters = [
+    {
+      jsonPath: 'parent.nestedArray',
+      jsonValue: '[1, 2, 3]'
+    }
+  ]
+
+  // Any of these will work
+  const metadataFilters = [
+    {
+      jsonPath: 'parent.nestedArray',
+      jsonValue: '[1,2,3]'
+    },
+    {
+      jsonPath: 'parent.nestedArray',
+      jsonValue: JSON.stringify([1, 2, 3])
+    }
+  ]
+  // ANCHOR_END: filter-payment-metadata-object
+}