Nodejs Array Subset isSubsetOfarray()

Method Source Code

/*/*www.  j av  a 2  s. co m*/
 * Make an array method that can return whether or not a context array is a
 * subset of an input array.  To simplify the problem, you can assume that both
 * arrays will contain only strings.
 *
 * 
 * var a = ['commit','push']
 * a.isSubsetOf(['commit','rebase','push','blame']) // true
 *
 * NOTE: You should disregard duplicates in the set.
 *
 * var b = ['merge','reset','reset']
 *
 * b.isSubsetOf(['reset','merge','add','commit']) // true 
 *
 * See http://en.wikipedia.org/wiki/Subset for more on the definition of a
 * subset.
*/

/*
 * Extra credit: Make the method work for arrays that contain any value,
 * including non-strings.
*/

Array.prototype.isSubsetOf = array => {
  let hash = {};
  let result = true;
  array.forEach(item => {
    hash.item ? hash.item++ : hash.item = 0;
  });
  this.forEach(item => {
    hash.item ? hash.item++ : result = false;
  });
  return result;
};

Related

1. isSubsetOf(input)

   Array.prototype.isSubsetOf = function(input) {
     var freq = {};
     for (var i = 0; i < this.length; i++) {
       freq[this[i]] = 1;
     for (var j = 0; j < input.length; j++) {
       if (freq[input[j]]) {
         delete freq[input[j]];
     return Object.keys(freq).length === 0;
   };
   

2. isSubsetOf(inputArray)

   Array.prototype.isSubsetOf = function(inputArray) {
     var exists = true;
     for (var i = 0; i < this.length; i++) {
       if (inputArray.indexOf(this[i]) === -1) {
         exists = false;
     return exists;
   };
   ...
   

3. isSubsetOf(inputArray)

   Array.prototype.isSubsetOf = function(inputArray) {
     for (var i = 0; i < this.length; i++) {
       var contains = false;
       for (var j = 0; j < inputArray.length; j++) {
         if (inputArray[j] === this[i]) {
           contains = true;
       if (!contains) {
   ...
   

4. isSubsetOf(matchArr)

   Array.prototype.isSubsetOf = function (matchArr) {
     var arr = this;
     for (var i = 0; i < arr.length; i++) {
       if (matchArr.indexOf(arr[i]) === -1 && typeof arr[i] !== 'object') {
         return false;
     return true;
   };
   ...
   

5. isSubsetOf(subset)

   'use strict';
   Array.prototype.isSubsetOf = function(subset){
     var arr = this;
   };