feat: allow for registry override (#369)

README.md

@@ -121,6 +121,7 @@ type AssetTransferApiOpts = {
 	/**
 	 * The injectedRegistry allows you to add custom values to the predefined initialized registry.
 	 * If you would like to see the registry you may visit https://github.com/paritytech/asset-transfer-api-registry/blob/main/registry.json
+	 * When adding a new chain, the `specName` and `tokens` fields are mandatory.
 	 * 
 	 * An example input of the registry would be:
 	 * {
@@ -133,9 +134,31 @@ type AssetTransferApiOpts = {
 	 *     }
 	 * }
 	 * 
-	 * NOTE: It supports adding info for `polkadot`, `kusama`, and `westend`.
+	 * NOTE: It supports adding info for `polkadot`, `kusama`, `westend` and `rococo`.
 	 */
 	injectedRegistry?: RequireAtLeastOne<ChainInfoRegistry>;
+	/**
+	 * The overrideRegistry option allows you to modify chain data already present in the registry,
+	 * either overriding fields' values or adding new information. If the chain of which data is
+	 * being overriden is not present in the registry, it will be treated as if it were
+	 * and injectedRegistry and added following the same logic.
+	 * 
+	 * If the chain is present in the registry, it will override only the fields
+	 * present in the passed overrideRegistry, leaving the remaining as is.
+	 * 
+	 * An example input for overrideRegistry would be:
+	 * {
+	 *     westend: {
+	 *         '0': {
+	 *             tokens: ['WER'],
+	 *         }
+	 *     }
+	 * }
+	 * 
+	 * This would override the existing native token for the Westend Relay Chain
+	 * to WER instead of WND.
+	 */
+	overrideRegistry?: RequireAtLeastOne<ChainInfoRegistry<InjectedChainInfoKeys>>;
 	/**
 	 * RegistryTypes is a string and can either be 'CDN' or 'NPM'.
 	 *