salix/loopback/common/methods/vn-model/getSetValues.js

module.exports = Self => {
    /**
     * Returns a set of allowed values defined on table scheme
     * @param {String} column - Model or Table column name
     * @return {Array} - Array of set values
     */
    Self.getSetValues = async function(column) {
        let model = this.app.models[this.modelName].definition;
        let properties = model.properties;
        let columnName;
        let tableName = this.modelName;
        let schema = null;

        if (model.settings && model.settings.mysql) {
            let tableSplit = model.settings.mysql.table.split('.');
            tableName = tableSplit.pop();
            schema = tableSplit.pop() || null;
        }

        if (properties[column]) {
            columnName = column;

            if (properties[column].mysql)
                columnName = properties[column].mysql.columnName;
        }

        let findColumn = Object.keys(properties).find(prop => {
            return properties[prop].mysql && properties[prop].mysql.columnName === column;
        });

        if (findColumn)
            columnName = properties[findColumn].mysql.columnName;

        let type = await this.rawSql(
            `SELECT DISTINCT column_type FROM information_schema.columns
                WHERE table_name = ? 
                    AND table_schema = IFNULL(?, DATABASE())
                    AND column_name = ?`,
            [tableName, schema, columnName]
        );

        if (!type) return;

        let setValues;
        setValues = type[0].column_type;
        setValues = setValues.replace(/set\((.*)\)/i, '$1');
        setValues = setValues.replace(/'/g, '');
        setValues = setValues.match(new RegExp(/(\w+)+/, 'ig'));

        let values = [];
        setValues.forEach(setValue => {
            values.push({value: setValue});
        });

        return values;
    };
};