Nodejs Array Flatten flatten()

Method Source Code

/**/*from  ww w  .  j av  a  2s  . co  m*/
Given an array of arrays, return all elements in a single array. You must use recursion.
*/

function flatten (arrays, call) {
  call = call + 1 || 0;
  if(arrays.length === 0 && !call) return null;
  return arrays.reduce(function(flat, cur){
    if(!Array.isArray(cur)) return flat.concat(cur);
    return flat.concat(flatten(cur, call));
  }, []);
}

Array.prototype.flatten = function(){
   return this.reduce(function(flat, val, i, hilly){
      Array.isArray(val) ? flat.concat(val.flatten()) : flat.concat(val);
   }, []);
}

Related

1. flatten()

   Array.prototype.flatten = function () {
     return this.reduce(function (flat, toFlatten) {
         return flat.concat(Array.isArray(toFlatten) ? toFlatten.flatten() : toFlatten);
     }, []);
   var array = [1, 2, 3, 4];
   console.log(array.flatten());
   var array = [1, 2, [3, 4], [5, 6]];
   console.log(array.flatten());
   ...
   

2. flatten()

   Array.prototype.flatten = function()
     var flat = new Array();
     for (var i = 0; i < this.length; i++) {
       for (var j = 0; j < this[i].length; j++) {
         flat.push(this[i][j]);
     return flat;
   ...
   

3. flatten()

   Array.prototype.flatten = function () { 
     return this.map((a) => (a.constructor.name == 'Array' && a.length == 1) ? a[0] : a) 
   

4. flatten()

   Array.prototype.flatten = function () {
       var flattenedArray = [];
       function copyArray(arr) {
           for (var i = 0; i < arr.length; i += 1) {
               if (arr[i] instanceof Array) {
                   copyArray(arr[i]);
               } else {
                   flattenedArray.push(arr[i]);
       copyArray(this);
       return flattenedArray;
   };
   var arr1 = [1, 2, [3, 4], 5];
   console.log('Original:');
   console.log(arr1);
   console.log();
   console.log('Flattened:');
   console.log(arr1.flatten());
   

5. flatten()

   var outputArray = [];
   Array.prototype.flatten = function (){
       function getValues(array){
           var i;
           for (i = 0; i < array.length; i += 1){
               var value = array[i];
               if (Array.isArray(value)){
                   getValues(value);
               else{
                   outputArray.push(value);
       getValues(this);
       return outputArray;
   var array = [0, ["string", "values"], 5.5, [[1, 2, true], [3, 4, false]], 10];
   console.log(array.flatten());
   

6. flatten()

   Array.prototype.flatten = function() {
       var newArray = [];
       function extractValues( arr ) {
           for (var i = 0, len = arr.length; i < len; i++) {
               var val = arr[ i ];
               if (val instanceof Array) {
                   extractValues( val );
               } else {
                   newArray.push( val );
   ...
   

7. flatten()

   isArray =  function(obj) {
       return toString.call(obj) === '[object Array]';
   };
   var flatten = function(arr) {
       return arr.reduce(function(memo, value) {
           if (isArray(value)) {
               return memo.concat(flatten(value));
           else {
   ...
   

8. flatten()

   Array.prototype.flatten = function(){
       var flattenedArray = [];
       function flattenArrays(arr) {
           for (var i = 0; i < arr.length; i++) {
               var currentValue = arr[i];
               if(Array.isArray(currentValue)){
                   flattenArrays(currentValue);
               }else{
                   flattenedArray.push(currentValue);
   ...
   

9. flatten()

   Array.prototype.flatten = function() {
     var merged = []
     return merged.concat.apply(merged, this)