Add regex expression option to autocompleters (https://github.com/woocommerce/woocommerce-admin/pull/1380)

plugins/woocommerce-admin/packages/components/src/search/autocomplete.js

@@ -193,7 +193,10 @@ export class Autocomplete extends Component {
 			}
 		}
 		// create a regular expression to filter the options
-		const search = new RegExp( escapeRegExp( query ), 'i' );
+		const expression = 'undefined' !== typeof completer.getSearchExpression
+			? completer.getSearchExpression( escapeRegExp( query ) )
+			: escapeRegExp( query );
+		const search = new RegExp( expression, 'i' );
 		// filter the options we already have
 		const filteredOptions = filterOptions( search, this.state.options, selected );
 		// update the state

plugins/woocommerce-admin/packages/components/src/search/autocompleters/countries.js

@@ -23,6 +23,9 @@ export default {
 	options() {
 		return wcSettings.dataEndpoints.countries || [];
 	},
+	getSearchExpression( query ) {
+		return '^' + query;
+	},
 	getOptionKeywords( country ) {
 		return [ country.code, decodeEntities( country.name ) ];
 	},