Nodejs Array Group By groupBy(fieldName)

Method Source Code

Array.prototype.groupBy = function (fieldName) {
    if (this.some(item => item.hasOwnProperty(fieldName))) {
        let uniqVal = this.map(item => item[fieldName]).filter((value, item, array) => array.indexOf(value) === item);
        let tempObj = {};//from  ww w  . ja  va2  s .  c  om
        uniqVal.map(item => tempObj[item] = []);
        this.forEach(item => {
            for (let name in tempObj) {
                if (item[fieldName] == name) {
                    tempObj[name].push(item);
                }
            }
        });
        return tempObj;
    } else {
        console.log('Not exist field:', fieldName);
        return this;
    }
    ;
};

Related

1. groupBy(callback)

   Array.prototype.groupBy = function(callback) {
       let obj = {}
       this.forEach(el => {
           let index = callback(el)
           if (!obj.hasOwnProperty(index)) {
               obj[index] = []
           obj[index].push(el)
       })
   ...
   

2. groupBy(callback)

   Array.prototype.groupBy = function(callback){
   var results = {};
     this.forEach(function (el){
       var key = callback(el);
       if (key in results === false) {
         results[key] = [];
       results[key].push(el);
    });
   ...
   

3. groupBy(callback)

   Array.prototype.groupBy = function(callback){
       this.reduce() 
   var result{}
   this.forEach(v, i, arr) = function(){}
   v, i, arr
   Array.prototype.groupBy = function(callback){ 
     var evens = Array.groupBy.forEach([9])
     if(Array.groupBy %2 === 0){
   ...
   

4. groupBy(fieldkey,fieldsums,fn)

   Array.prototype.groupBy=function(fieldkey,fieldsums,fn){
     var groups = _.groupBy(this,function(item){
       return item[fieldkey];
     });
     async.map(_.keys(groups)
       ,function(key,callback){
         var value = groups[key];
         var r = {};
         r[fieldkey] = key;
   ...
   

5. groupBy(fn)

   Array.prototype.groupBy = function (fn) {
     var result = {
     };
     for (var i = 0; i < this.length; i++)
       try {
         if (!result[fn(this[i])])
           result[fn(this[i])] = [
   ...
   

6. groupBy(fn)

   Array.prototype.groupBy = function(fn) {
     if (!fn) return this.groupBy(x => x)
     return this.reduce((acc, x) => {
       if (acc[fn(x)]) return acc
       acc[fn(x)] = this.filter(i => {
         return fn(x) === fn(i)
       })
       return acc
     }, {})
   ...
   

7. groupBy(funcProp)

   Array.prototype.groupBy = function (funcProp) {
     return this.reduce(function (accumulator, value) {
       (accumulator[funcProp(value)] = accumulator[funcProp(value)] || []).push(value);
       return accumulator;
     }, {});
   };
   Array.prototype.orderBy = function (funcProp, desc = false) {
     return this.sort((a, b) => {
       var aValue = funcProp(a);
   ...