Nodejs Array Flatten flatten()

Method Source Code

//https://egghead.io/lessons/javascript-create-an-array-concatall-method

//nested data structure representing stock exchanges
var exchanges = [
   [//  w  ww  . j  a va2  s . c  o  m
      {symbol: "JNJ", price: 2030.00, volume:48984}, 
       {symbol: "PWC", price: 4340.00, volume:15985}
   ],
   [
      {symbol: "CISC", price: 4563.00, volume:874651},
      {symbol: "KROG", price: 712.00, volume:8949}
   ]
];


Array.prototype.flatten = function() {
   var results = [];
   (function recur(obj) {
      if(Array.isArray(obj)) {
         obj.forEach(function(element) {
            recur(element);
         });
      } else {
         results.push(obj);
      }      
   })(this);
   return results;
};

console.log(exchanges.
            flatten().
            filter(function(stock) {
               return stock.price > 2500.00;
            }).
            map(function(stock) {
               return stock.price;
            }).
            reduce((a, b) => (a + b), 0)   //like a fold operation
         );

Related

1. flatten()

   Array.prototype.flatten = function() {
       var resultArray = [];
       function getValues(array) {
           var i;
           for (i = 0; i < array.length; i += 1) {
               var value = array[i];
               if (Array.isArray(value)) {
                   getValues(value);
               } else {
   ...
   

2. flatten()

   Array.prototype.flatten = function() {
     var toString = Object.prototype.toString;
     var arrayTypeStr = '[object Array]';
     var result = [];
     var nodes = this.slice();
     var node;
     if (!this.length) {
       return result;
     node = nodes.pop();
     do {
       if (toString.call(node) === arrayTypeStr) {
         nodes.push.apply(nodes, node);
       } else {
         result.push(node);
     } while (nodes.length && (node = nodes.pop()) !== undefined);
     result.reverse();
     return result;
   

3. flatten()

   Array.prototype.flatten = function() {
       var originalArray = this,
           newArray = [],
           i = 0,
           j = 0,
           element,
           temp;
       for (i = 0; i < originalArray.length; i+=1) {
           element = originalArray[i];
   ...
   

4. flatten()

   Array.prototype.flatten = function() {
       var originalArray = this;
       var newArray = [];
       var i = 0;
       var j = 0;
       var element;
       var temp;
       for (i = 0; i < originalArray.length; i+=1) {
           element = originalArray[i];
   ...
   

5. flatten()

   Array.prototype.flatten = function() {
       var resultArray = [];
       innerFlatten(this);
       function innerFlatten(arr) {
           arr.forEach(function(el) {
               if(Array.isArray(el)) {
                   innerFlatten(el);
               } else {
                   resultArray.push(el);
   ...
   

6. flatten()

   Array.prototype.flatten = function(){
     var result = [];
     this.forEach(function(x) {
       result = result.concat(x);
     });
     return result;
   };
   

7. flatten()

   Array.prototype.flatten = function () {
       return this.reduce((p,c) => p.concat(c), [])
   

8. flatten()

   Array.prototype.flatten = function () {
       function flattenArrayOfArrays(array, result) {
           if (!result) {
               result = [];
           for (var i = 0; i < array.length; i++) {
               if (Array.isArray(array[i])) {
                   flattenArrayOfArrays(array[i], result);
               } else {
   ...
   

9. flatten()

   Array.prototype.flatten = function() {
     return this.reduce(function(res, el) {
       if(el.constructor == Array) {
         el.forEach(function(sub_el) {
           res.push(sub_el);
         })
       } else {
         res.push(el);
       return res;
     }, []);