Nodejs Array Subset isSubsetOf(array)

Method Source Code

/*/*from  w  w w  .j  a v 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.
 */

var a = ['commit', 'push'];
var b = ['merge', 'reset', 'reset'];

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

  return true;
};

console.log(a.isSubsetOf(['commit', 'rebase', 'push', 'blame', undefined]));
console.log(b.isSubsetOf(['commit', 'rebase', 'push', 'blame', 'reset', 'merge']));

Related

1. isSubsetOf(array)

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

2. isSubsetOf(array)

   Array.prototype.isSubsetOf = function(array) {
     var arr = this;
     var obj = {};
     for(var i=0; i<array.length; i++) {
       obj[array[i]] = true; 
     for(var i=0; i<arr.length; i++) {
       if(!(arr[i] in obj)) {
         return false;
   ...
   

3. isSubsetOf(array)

   Array.prototype.isSubsetOf = function (array) {
     var subset    = this;
     var subsetLen = subset.length;
     var supersetLen = array.length;
     var first, found;
     if ( subsetLen > supersetLen ) return false;
     if ( subsetLen === 0 && supersetLen >= 0 ) return true;
     first = subset[0];
     found = array.indexOf( first );
   ...
   

4. isSubsetOf(array)

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

5. isSubsetOf(array)

   Array.prototype.isSubsetOf = function(array) {
     function arrayContains(array, item) {
       for (var i = 0; i < array.length; i++) {
         if (array[i] === item) {
           return true;
       return false;
     for (var i = 0; i < this.length; i++) {
       if (!arrayContains(array, this[i])) {
         return false;
     return true;
   

6. isSubsetOf(bigArray)

   Array.prototype.isSubsetOf = function(bigArray) {
     var uniqueSub = this.unique();
     var uniqueBig = bigArray.unique();
     var status = true;
     this.forEach(function(item) {
       if(bigArray.indexOf(item) === -1) status = false;
     });
     return status;
   };
   ...
   

7. isSubsetOf(comparisonArray)

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

8. isSubsetOf(input)

   Array.prototype.isSubsetOf = function(input) {
     var isSub = true;
     this.forEach(function (el) {
       if (!input.includes(el)) {
         isSub = false;
     });
     return isSub;
   };
   ...
   

9. isSubsetOf(input)

   Array.prototype.isSubsetOf = function(input){
     let result = true;
     this.forEach(item => input.indexOf(item) !== -1 ? result = result && true : result = false);
     return result;