import ballerina/io;

final string:RegExp regSpaceSplitter = re ` `;
final string:RegExp regBracketSplitter = re `\(`;

public function main() {
    string desc = "1000 x cost comp (0.1 annual)";
    string cleanDesc = getCleanInvoiceItemDescription(desc);
    io:println("Clean Description: ", cleanDesc);
}

public function getCleanInvoiceItemDescription(string description) returns string {
    string[] descriptionParts = regBracketSplitter.split(description);
    string[] descriptionParts2 = regSpaceSplitter.split(descriptionParts[0]);
    string cleanDescription = string:'join(" ", ...descriptionParts2.slice(2));
    return cleanDescription;
}