ter = array_value($config, 'filter'); $arr = array_value($filter, $type); $enable = array_value($arr, 'enable'); $wordarr = array_value($arr, 'keyword'); if (0 == $enable || empty($wordarr)) return FALSE; foreach ($wordarr as $_keyword) { if (!$_keyword) continue; $r = strpos(strtolower($keyword), strtolower($_keyword)); if (FALSE !== $r) { $error = $_keyword; return TRUE; } } return FALSE; } // return http://domain.com OR https://domain.com function url_prefix() { $http = ((isset($_SERVER['HTTPS']) && 'on' == $_SERVER['HTTPS']) || (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https')) ? 'https://' : 'http://'; return $http . $_SERVER['HTTP_HOST']; } // 唯一身份ID function uniq_id() { return uniqid(substr(md5(microtime(true) . mt_rand(1000, 9999)), 8, 8)); } // 生成订单号 14位 function trade_no() { $trade_no = str_replace('.', '', microtime(1)); $strlen = mb_strlen($trade_no, 'UTF-8'); $strlen = 14 - $strlen; $str = ''; if ($strlen) { for ($i = 0; $i <= $strlen; $i++) { if ($i < $strlen) $str .= '0'; } } return $trade_no . $str; } // 生成订单号 16位 function trade_no_16() { $explode = explode(' ', microtime()); $trade_no = $explode[1] . mb_substr($explode[0], 2, 6, 'UTF-8'); return $trade_no; } // 当前年的天数 function date_year($time = NULL) { $time = intval($time) ? $time : time(); return date('L', $time) + 365; } // 当前年份中的第几天 function date_z($time = NULL) { $time = intval($time) ? $time : time(); return date('z', $time); } // 当前月份中的第几天，没有前导零 1 到 31 function date_j($time = NULL) { $time = intval($time) ? $time : time(); return date('j', $time); } // 当前月份中的第几天，有前导零的2位数字 01 到 31 function date_d($time = NULL) { $time = intval($time) ? $time : time(); return date('d', $time); } // 当前时间为星期中的第几天 数字表示 1表示星期一 到 7表示星期天 function date_w_n($time = NULL) { $time = intval($time) ? $time : time(); return date('N', $time); } // 当前日第几周 function date_d_w($time = NULL) { $time = intval($time) ? $time : time(); return date('W', $time); } // 当前几月 没有前导零1-12 function date_n($time = NULL) { $time = intval($time) ? $time : time(); return date('n', $time); } // 当前月的天数 function date_t($time = NULL) { $time = intval($time) ? $time : time(); return date('t', $time); } // 0 o'clock on the day function clock_zero() { return strtotime(date('Ymd')); } // 24 o'clock on the day function clock_twenty_four() { return strtotime(date('Ymd')) + 86400; } // 8点过期 / expired at 8 a.m. function eight_expired($time = NULL) { $time = intval($time) ? $time : time(); // 当前时间大于8点则改为第二天8点过期 $life = date('G') <= 8 ? (strtotime(date('Ymd')) + 28800 - $time) : clock_twenty_four() - $time + 28800; return $life; } // 24点过期 / expired at 24 a.m. function twenty_four_expired($time = NULL) { $time = intval($time) ? $time : time(); $twenty_four = clock_twenty_four(); $life = $twenty_four - $time; return $life; } /** * @param $url 提交地址 * @param string $post POST数组 / 空为GET获取数据 / $post='GET'获取连续跳转最终URL * @param string $cookie cookie * @param int $timeout 超时 * @param int $ms 设为1是毫秒 * @return mixed 返回数据 */ function https_request($url, $post = '', $cookie = '', $timeout = 30, $ms = 0) { if (empty($url)) return FALSE; if (version_compare(PHP_VERSION, '5.2.3', '<')) { $ms = 0; $timeout = 30; } is_array($post) and $post = http_build_query($post); // 没有安装curl 使用http的形式，支持post if (!extension_loaded('curl')) { //throw new Exception('server not install CURL'); if ($post) { return https_post($url, $post, $cookie, $timeout); } else { return http_get($url, $cookie, $timeout); } } is_array($cookie) and $cookie = http_build_query($cookie); $curl = curl_init(); // 返回执行结果，不输出 curl_setopt($curl, CURLOPT_RETURNTRANSFER, true); //php5.5跟php5.6中的CURLOPT_SAFE_UPLOAD的默认值不同 if (class_exists('\CURLFile')) { curl_setopt($curl, CURLOPT_SAFE_UPLOAD, true); } else { defined('CURLOPT_SAFE_UPLOAD') and curl_setopt($curl, CURLOPT_SAFE_UPLOAD, false); } // 设定请求的RUL curl_setopt($curl, CURLOPT_URL, $url); // 设定返回信息中包含响应信息头 if (ini_get('safe_mode') && ini_get('open_basedir')) { // $post参数必须为GET if ('GET' == $post) { // 安全模式时将头文件的信息作为数据流输出 curl_setopt($curl, CURLOPT_HEADER, true); // 安全模式采用连续抓取 curl_setopt($curl, CURLOPT_NOBODY, true); } } else { curl_setopt($curl, CURLOPT_HEADER, false); // 允许跳转10次 curl_setopt($curl, CURLOPT_MAXREDIRS, 10); // 使用自动跳转，返回最后的Location curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true); } $ua1 = 'Mozilla/5.0 (iPhone; CPU iPhone OS 13_2_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0.3 Mobile/15E148 Safari/604.1'; $ua = empty($_SERVER["HTTP_USER_AGENT"]) ? $ua1 : $_SERVER["HTTP_USER_AGENT"]; curl_setopt($curl, CURLOPT_USERAGENT, $ua); // 兼容HTTPS if (FALSE !== stripos($url, 'https://')) { curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE); curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, FALSE); //ssl版本控制 //curl_setopt($curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1); curl_setopt($curl, CURLOPT_SSLVERSION, true); } $header = array('Content-type: application/x-www-form-urlencoded;charset=UTF-8', 'X-Requested-With: XMLHttpRequest'); $cookie and $header[] = "Cookie: $cookie"; curl_setopt($curl, CURLOPT_HTTPHEADER, $header); if ($post) { // POST curl_setopt($curl, CURLOPT_POST, true); // 自动设置Referer curl_setopt($curl, CURLOPT_AUTOREFERER, true); curl_setopt($curl, CURLOPT_POSTFIELDS, $post); } if ($ms) { curl_setopt($curl, CURLOPT_NOSIGNAL, true); // 设置毫秒超时 curl_setopt($curl, CURLOPT_TIMEOUT_MS, intval($timeout)); // 超时毫秒 } else { curl_setopt($curl, CURLOPT_TIMEOUT, intval($timeout)); // 秒超时 } //优先解析 IPv6 超时后IPv4 //curl_setopt($curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4); curl_setopt($curl, CURLOPT_ENCODING, 'gzip'); // 返回执行结果 $output = curl_exec($curl); // 有效URL，输出URL非URL页面内容 CURLOPT_RETURNTRANSFER 必须为false 'GET' == $post and $output = curl_getinfo($curl, CURLINFO_EFFECTIVE_URL); curl_close($curl); return $output; } function save_image($img) { $ch = curl_init(); // 设定请求的RUL curl_setopt($ch, CURLOPT_URL, $img); // 设定返回信息中包含响应信息头 启用时会将头文件的信息作为数据流输出 //curl_setopt($ch, CURLOPT_HEADER, false); //curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER["HTTP_USER_AGENT"]); // true表示$html,false表示echo $html curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 10); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); //curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1); //curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0); curl_setopt($ch, CURLOPT_ENCODING, 'gzip'); $output = curl_exec($ch); curl_close($ch); return $output; } // 计算字串宽度:剧中对齐(字体大小/字串内容/字体链接/背景宽度/倍数) function calculate_str_width($size, $str, $font, $width, $multiple = 2) { $box = imagettfbbox($size, 0, $font, $str); return ($width - $box[4] - $box[6]) / $multiple; } // 搜索目录下的文件 比对文件后缀 function search_directory($path) { if (is_dir($path)) { $paths = scandir($path); foreach ($paths as $val) { $sub_path = $path . '/' . $val; if ('.' == $val || '..' == $val) { continue; } else if (is_dir($sub_path)) { //echo '目录名:' . $val . '
'; search_directory($sub_path); } else { //echo ' 最底层文件: ' . $path . '/' . $val . '
'; $ext = strtolower(file_ext($sub_path)); if (in_array($ext, array('php', 'asp', 'jsp', 'cgi', 'exe', 'dll'), TRUE)) { echo '异常文件：' . $sub_path . '
'; } } } } } // 一维数组转字符串 $sign待签名字符串 $url为urlencode转码GET参数字符串 function array_to_string($arr, &$sign = '', &$url = '') { if (count($arr) != count($arr, 1)) throw new Exception('Does not support multi-dimensional array to string'); // 注销签名 unset($arr['sign']); // 排序 ksort($arr); reset($arr); // 转字符串做签名 $url = ''; $sign = ''; foreach ($arr as $key => $val) { if (empty($val) || is_array($val)) continue; $url .= $key . '=' . urlencode($val) . '&'; $sign .= $key . '=' . $val . '&'; } $url = substr($url, 0, -1); $url = htmlspecialchars($url); $sign = substr($sign, 0, -1); } // 私钥生成签名 function rsa_create_sign($data, $key, $sign_type = 'RSA') { if (!function_exists('openssl_sign')) throw new Exception('OpenSSL extension is not enabled'); if (!defined('OPENSSL_ALGO_SHA256')) throw new Exception('Only versions above PHP 5.4.8 support SHA256'); $key = wordwrap($key, 64, "\n", true); if (FALSE === $key) throw new Exception('Private Key Error'); $key = "-----BEGIN RSA PRIVATE KEY-----\n$key\n-----END RSA PRIVATE KEY-----"; if ('RSA2' == $sign_type) { openssl_sign($data, $sign, $key, OPENSSL_ALGO_SHA256); } else { openssl_sign($data, $sign, $key, OPENSSL_ALGO_SHA1); } // 加密 return base64_encode($sign); } // 公钥验证签名 function rsa_verify_sign($data, $sign, $key, $sign_type = 'RSA') { $key = wordwrap($key, 64, "\n", true); if (FALSE === $key) throw new Exception('Public Key Error'); $key = "-----BEGIN PUBLIC KEY-----\n$key\n-----END PUBLIC KEY-----"; // 签名正确返回1 签名不正确返回0 错误-1 if ('RSA2' == $sign_type) { $result = openssl_verify($data, base64_decode($sign), $key, OPENSSL_ALGO_SHA256); } else { $result = openssl_verify($data, base64_decode($sign), $key, OPENSSL_ALGO_SHA1); } return $result === 1; } // Array to xml array('appid' => 'appid', 'code' => 'success') function array_to_xml($arr) { if (!is_array($arr) || empty($arr)) throw new Exception('Array Error'); $xml = ""; foreach ($arr as $key => $val) { if (is_numeric($val)) { $xml .= "<" . $key . ">" . $val . ""; } else { $xml .= "<" . $key . ">"; } } $xml .= ""; return $xml; } // Xml to array function xml_to_array($xml) { if (!$xml) throw new Exception('XML error'); $old = libxml_disable_entity_loader(true); // xml解析 $result = (array)simplexml_load_string($xml, null, LIBXML_NOCDATA | LIBXML_COMPACT); // 恢复旧值 if (FALSE === $old) libxml_disable_entity_loader(false); return $result; } // 逐行读取 function well_import($file) { if ($handle = fopen($file, 'r')) { while (!feof($handle)) { yield trim(fgets($handle)); } fclose($handle); } } // 计算总行数 function well_import_total($file, $key = 'well_import_total') { static $cache = array(); if (isset($cache[$key])) return $cache[$key]; $count = cache_get($key); if (NULL === $count) { $count = 0; $globs = well_import($file); while ($globs->valid()) { ++$count; $globs->next(); // 指向下一个 } $count and cache_set($key, $count, 300); } return $cache[$key] = $count; } $g_dir_file = FALSE; function well_search_dir($path) { global $g_dir_file; FALSE === $g_dir_file and $g_dir_file = array(); if (is_dir($path)) { $paths = scandir($path); foreach ($paths as $val) { $sub_path = $path . '/' . $val; if ('.' == $val || '..' == $val) { continue; } else if (is_dir($sub_path)) { well_search_dir($sub_path); } else { $g_dir_file[] = $sub_path; } } } return $g_dir_file; } ?>javascript - Group and aggregate array of objects by key names - Stack Overflow

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    javascript - Group and aggregate array of objects by key names - Stack Overflow

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    I would like to write a function in JS that takes lists of names as arguments and is able to group by and aggregate by the specified column names. For example, my data might look like: 

    const SALES = [
  { lead: 'Mgr 1', revenue: 49.99, repName: 'Rep 1', forecast: 81.00 },
  { lead: 'Mgr 1', revenue: 9.99, repName: 'Rep 1', forecast: 91.00 },
  { lead: 'Mgr 1', revenue: 9.99, repName: 'Rep 13', forecast: 82.00 },
  { lead: 'Mgr 2', revenue: 99.99, repName: 'Rep 3', forecast: 101.00 },
  { lead: 'Mgr 2', revenue: 9.99, repName: 'Rep 5', forecast: 89.00 },
  { lead: 'Mgr 3', revenue: 199.99, repName: 'Rep 6', forecast: 77.00 }
];

    I can group and aggregate this data like this:

    let grouped = {};
SALES.forEach(({lead, repName, revenue}) => {
  grouped[[lead, repName]] = grouped[[lead, repName]] || { lead, repName, revenue: 0 };
  grouped[[lead, repName]].revenue = +grouped[[lead, repName]].revenue + (+revenue);
});
grouped = Object.values(grouped);

console.warn('Look at this:\n', grouped);

    However, I would like this to be more dynamic so that I don't have to write an if-else statement for all the possible binations of groupings and aggregations. The following code shows something that I would like to get working, but currently does not. 

    function groupByTotal(arr, groupByCols, aggregateCols) {
  let grouped = {};
  arr.forEach(({ groupByCols, aggregateCols }) => {
    grouped[groupByCols] = grouped[groupByCols] || { groupByCols, aggregateCols: 0 };
    grouped[groupByCols].aggregateCols = +grouped[groupByCols].aggregateCols + (+aggregateCols);
  });
  grouped = Object.values(grouped);
  return grouped;
}

groupByTotal(SALES,['lead','repName'],'revenue')

    Expected output might look like this:

    [
  { lead: "Mgr 1", repName: "Rep 1", revenue: 59.98 },
  { lead: "Mgr 1", repName: "Rep 13", revenue: 9.99 },
  { lead: "Mgr 2", repName: "Rep 3", revenue: 99.99 },
  { lead: "Mgr 2", repName: "Rep 5", revenue: 9.99 },
  { lead: "Mgr 3", repName: "Rep 6", revenue: 199.99 }
]

    Ideally, I would like to be able to pass in any number of column names to group by or to be aggregated. Any help would be greatly appreciated.

    I would like to write a function in JS that takes lists of names as arguments and is able to group by and aggregate by the specified column names. For example, my data might look like: 

    const SALES = [
  { lead: 'Mgr 1', revenue: 49.99, repName: 'Rep 1', forecast: 81.00 },
  { lead: 'Mgr 1', revenue: 9.99, repName: 'Rep 1', forecast: 91.00 },
  { lead: 'Mgr 1', revenue: 9.99, repName: 'Rep 13', forecast: 82.00 },
  { lead: 'Mgr 2', revenue: 99.99, repName: 'Rep 3', forecast: 101.00 },
  { lead: 'Mgr 2', revenue: 9.99, repName: 'Rep 5', forecast: 89.00 },
  { lead: 'Mgr 3', revenue: 199.99, repName: 'Rep 6', forecast: 77.00 }
];

    I can group and aggregate this data like this:

    let grouped = {};
SALES.forEach(({lead, repName, revenue}) => {
  grouped[[lead, repName]] = grouped[[lead, repName]] || { lead, repName, revenue: 0 };
  grouped[[lead, repName]].revenue = +grouped[[lead, repName]].revenue + (+revenue);
});
grouped = Object.values(grouped);

console.warn('Look at this:\n', grouped);

    However, I would like this to be more dynamic so that I don't have to write an if-else statement for all the possible binations of groupings and aggregations. The following code shows something that I would like to get working, but currently does not. 

    function groupByTotal(arr, groupByCols, aggregateCols) {
  let grouped = {};
  arr.forEach(({ groupByCols, aggregateCols }) => {
    grouped[groupByCols] = grouped[groupByCols] || { groupByCols, aggregateCols: 0 };
    grouped[groupByCols].aggregateCols = +grouped[groupByCols].aggregateCols + (+aggregateCols);
  });
  grouped = Object.values(grouped);
  return grouped;
}

groupByTotal(SALES,['lead','repName'],'revenue')

    Expected output might look like this:

    [
  { lead: "Mgr 1", repName: "Rep 1", revenue: 59.98 },
  { lead: "Mgr 1", repName: "Rep 13", revenue: 9.99 },
  { lead: "Mgr 2", repName: "Rep 3", revenue: 99.99 },
  { lead: "Mgr 2", repName: "Rep 5", revenue: 9.99 },
  { lead: "Mgr 3", repName: "Rep 6", revenue: 199.99 }
]

    Ideally, I would like to be able to pass in any number of column names to group by or to be aggregated. Any help would be greatly appreciated.

    • javascript
    • arrays
    Share Improve this question edited Sep 6, 2019 at 17:27 ErrorJordan asked Sep 6, 2019 at 14:26 ErrorJordanErrorJordan 6415 silver badges15 bronze badges 0
    Add a ment  | 

    2 Answers 2

    Reset to default 5

    Currently you are creating a key based on the stringified value of [lead, repName]. You could get this dynamically based on groupByCols

    // gets the values for "groupByCols" seperated by `|` to create a unique key
const values = groupByCols.map(k => o[k]).join("|");

    You'd also need to get a subset of the object based on groupByCols

    const subSet = (o, keys) => keys.reduce((r, k) => (r[k] = o[k], r), {})

// OR if fromEntries() is supported
const subSet = (o, keys) => Object.fromEntries(keys.map(k => [k, o[k]))

    Rest of the logic would be similar to what you're already doing. Use the unique in grouped. Get the subset of the object and add/update aggregateCols key based on whether the key already exists or not

    const SALES = [
  { lead: 'Mgr 1', revenue: 49.99, repName: 'Rep 1', forecast: 81.00 },
  { lead: 'Mgr 1', revenue: 9.99, repName: 'Rep 1', forecast: 91.00 },
  { lead: 'Mgr 1', revenue: 9.99, repName: 'Rep 13', forecast: 82.00 },
  { lead: 'Mgr 2', revenue: 99.99, repName: 'Rep 3', forecast: 101.00 },
  { lead: 'Mgr 2', revenue: 9.99, repName: 'Rep 5', forecast: 89.00 },
  { lead: 'Mgr 3', revenue: 199.99, repName: 'Rep 6', forecast: 77.00 }
];

const subSet = (o, keys) => keys.reduce((r, k) => (r[k] = o[k], r), {})

function groupByTotal(arr, groupByCols, aggregateCols) {
  let grouped = {};

  arr.forEach(o => {
    const values = groupByCols.map(k => o[k]).join("|");
    if (grouped[values])
      grouped[values][aggregateCols] += o[aggregateCols]
    else
      grouped[values] = { ...subSet(o, groupByCols), [aggregateCols]: o[aggregateCols] }
  })

  return Object.values(grouped);
}

console.log("Sum revenue based on lead and repName")
console.log(groupByTotal(SALES, ['lead', 'repName'], 'revenue'))

console.log("Sum forecast based on lead: ")
console.log(groupByTotal(SALES, ['lead'], 'forecast'))

    If you want to pass a array of columns to sum, you can loop through aggregateCols and sum each property in grouped:

    if (grouped[values]) {
    aggregateCols.forEach(col => grouped[values][col] += o[col])
    grouped[values].Count++
} else {
    grouped[values] = subSet(o, groupByCols);
    grouped[values].Count = 1
    aggregateCols.forEach(col => grouped[values][col] = o[col])
}

    You can implement a similar algorithm using pure JavaScript.

    Just know how to create your key and aggregate the data as in the following scenario.

    const SALES = [
  { lead: 'Mgr 1', revenue:  49.99, repName: 'Rep 1',  forecast: 81.00 },
  { lead: 'Mgr 1', revenue:   9.99, repName: 'Rep 1',  forecast: 91.00 },
  { lead: 'Mgr 1', revenue:   9.99, repName: 'Rep 13', forecast: 82.00 },
  { lead: 'Mgr 2', revenue:  99.99, repName: 'Rep 3',  forecast: 101.00 },
  { lead: 'Mgr 2', revenue:   9.99, repName: 'Rep 5',  forecast: 89.00 },
  { lead: 'Mgr 3', revenue: 199.99, repName: 'Rep 6',  forecast: 77.00 }
];

console.log(aggregate(SALES, ['lead', 'repName'], 'revenue'));

function aggregate(data, keyFields, accumulator) {
  var createNewObj = (ref, fields) => {
    return fields.reduce((result, key) => {
      return Object.assign(result, { [key] : ref[key] });
    }, {});
  }
  return Object.values(data.reduce((result, object, index, ref) => {
    let key = keyFields.map(key => object[key]).join('');
    let val = result[key] || createNewObj(object, keyFields);
    val[accumulator] = (val[accumulator] || 0) + object[accumulator];
    return Object.assign(result, { [key] : val });
  }, {}));
}
    .as-console-wrapper { top: 0; max-height: 100% !important; }

    Result

    [
  {
    "lead": "Mgr 1",
    "repName": "Rep 1",
    "revenue": 59.98
  },
  {
    "lead": "Mgr 1",
    "repName": "Rep 13",
    "revenue": 9.99
  },
  {
    "lead": "Mgr 2",
    "repName": "Rep 3",
    "revenue": 99.99
  },
  {
    "lead": "Mgr 2",
    "repName": "Rep 5",
    "revenue": 9.99
  },
  {
    "lead": "Mgr 3",
    "repName": "Rep 6",
    "revenue": 199.99
  }
]

    Alternative with custom accumulator function

    The following example uses an accumulator object that contains a reference field and a function that applies a mathematical expression.

    {
  key: 'revenue',
  fn : (total, value) => total + value
}


    const SALES = [
  { lead: 'Mgr 1', revenue:  49.99, repName: 'Rep 1',  forecast: 81.00 },
  { lead: 'Mgr 1', revenue:   9.99, repName: 'Rep 1',  forecast: 91.00 },
  { lead: 'Mgr 1', revenue:   9.99, repName: 'Rep 13', forecast: 82.00 },
  { lead: 'Mgr 2', revenue:  99.99, repName: 'Rep 3',  forecast: 101.00 },
  { lead: 'Mgr 2', revenue:   9.99, repName: 'Rep 5',  forecast: 89.00 },
  { lead: 'Mgr 3', revenue: 199.99, repName: 'Rep 6',  forecast: 77.00 }
];

console.log(aggregate(SALES, ['lead', 'repName'], {
  key: 'revenue',
  fn : (total, value) => total + value
}));

function aggregate(data, keyFields, accumulator) {
  var createNewObj = (ref, fields) => {
    return fields.reduce((result, key) => {
      return Object.assign(result, { [key] : ref[key] });
    }, {});
  }
  return Object.values(data.reduce((result, object, index, ref) => {
    let key = keyFields.map(key => object[key]).join('');
    let val = result[key] || createNewObj(object, keyFields);
    val[accumulator.key] = accumulator.fn(val[accumulator.key] || 0, object[accumulator.key]);
    return Object.assign(result, { [key] : val });
  }, {}));
}
    .as-console-wrapper { top: 0; max-height: 100% !important; }

    Another functional approach

    If you want to accumulate multiple fields, you will need to drop the field to reference and just modify the entire object, but this is typically more dangerous.

    const SALES = [
  { lead: 'Mgr 1', revenue:  49.99, repName: 'Rep 1',  forecast: 81.00 },
  { lead: 'Mgr 1', revenue:   9.99, repName: 'Rep 1',  forecast: 91.00 },
  { lead: 'Mgr 1', revenue:   9.99, repName: 'Rep 13', forecast: 82.00 },
  { lead: 'Mgr 2', revenue:  99.99, repName: 'Rep 3',  forecast: 101.00 },
  { lead: 'Mgr 2', revenue:   9.99, repName: 'Rep 5',  forecast: 89.00 },
  { lead: 'Mgr 3', revenue: 199.99, repName: 'Rep 6',  forecast: 77.00 }
];

console.log(aggregate(SALES, ['lead', 'repName'], (prev, curr) => {
  return Object.assign(prev, {
    revenueTotal : (prev['revenueTotal'] || 0) + curr['revenue'],
    forecastMax : Math.max((prev['forecastMax'] || -Number.MAX_VALUE), curr['forecast']),
    forecastMin : Math.min((prev['forecastMin'] || +Number.MAX_VALUE), curr['forecast'])
  });
}));

function aggregate(data, keyFields, accumulatorFn) {
  var createNewObj = (ref, fields) => {
    return fields.reduce((result, key) => {
      return Object.assign(result, { [key] : ref[key] });
    }, {});
  }
  return Object.values(data.reduce((result, object, index, ref) => {
    let key = keyFields.map(key => object[key]).join('');
    let val = result[key] || createNewObj(object, keyFields);
    return Object.assign(result, { [key] : accumulatorFn(val, object) });
  }, {}));
}
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