gistfile1.txt

let unionedData = _.union(fcas.data.data, dev.data.data, maturity.data.data, utility.data.data);

// reduce data.data
let reducer = (map, obj) => {
    let projObj = {};
    if(map.hasOwnProperty(obj.project_id)) {
      projObj = map[obj.project_id];
    }

    projObj.project_id = obj.project_id;
    projObj.project_name = obj.project_name;
    projObj.symbol = obj.symbol;
    projObj[obj.metric_slug] = obj.value;

    map[obj.project_id] = projObj;

    return map;
};

var uniqueData = unionedData.reduce(reducer, {});