Retrieve OptionSet Metadata using JavaScript – Dynamics 365 CE/Microsoft Dynamics CRM

function getOptionSetMetadata(schemaName) {
    var schemaName = "industrycode"; // You can pass this as a parameter to this function and comment this line.

    var optionSetFetch = `<fetch version='1.0' output-format='xml-platform' mapping='logical' distinct='false'>
        <entity name='stringmap' >
            <attribute name='attributevalue' />
            <attribute name='value' />
            <filter type='and' >
                <condition attribute='attributename' operator='eq' value= '${schemaName}' />
            </filter>
        </entity>
    </fetch>`;
    optionSetFetch = "?fetchXml=" + encodeURIComponent(optionSetFetch);

    Xrm.WebApi.retrieveMultipleRecords("stringmap", optionSetFetch).then(
        function success(result) {
            if (result.entities.length > 0) {
                console.log(result.entities);
                for (count = 0; count < result.entities.length; count++) {
                    console.log("Attribute Value : " + result.entities[count].attributevalue);
                    console.log("Value : " + result.entities[count].value);
                }
            }
        },
        function (error) {
            console.log(error.message);
        });
}