Nodejs Array Subset isSubsetOf(arr)

Method Source Code

/*/*from  ww  w  .j  ava 2 s. com*/
 * 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 neither
 * array will contain objects or arrays as elements within them.
 *
 *
 * 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 objects and/or arrays as elements.
*/

Array.prototype.isSubsetOf = function (arr) {
  // your code here

  var objectify = function (arr) {
    var obj = {};
    for (var i = 0; i < arr.length; i++) {
      obj[arr[i]] = true;
    }
    return obj;
  };
  // transform `arr` to be an object `obj` for speed
  var obj = objectify(arr);
  // for each element in `this`
  for (var i = 0; i < this.length; i++) {
    // if element is not in `obj` return false
    if (obj[this[i]] === undefined) { return false; }
  }
  // assuming we?ve completed the for loop return true
  return true;
};

Related

1. isSubsetOf(arr)

   Array.prototype.isSubsetOf = function(arr) {
     return isSubsetObjs(this, objectify(arr));
   };
   var isSubsetObjs = function(arr, obj2) {
     for (var i = 0; i < arr.length; i++) {
       if (!obj2.hasOwnProperty(arr[i])) { 
        return false; 
     } return true;
   ...
   

2. isSubsetOf(arr)

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

3. isSubsetOf(arr)

   Array.prototype.isSubsetOf = function (arr) {
     var objectify = function(arr) {
       var obj = {};
       for (var i = 0; i < arr.length; i++) {
         obj[arr[i]] = true;
       return obj;
     };
     var obj = objectify(arr);
   ...
   

4. isSubsetOf(arr)

   Array.prototype.isSubsetOf = function (arr) {
     let result = 0;
     for (let i = 0; i < this.length; i += 1) {
       for (let p = 0; p < arr.length; p += 1) {
         if (this[i] === arr[p]) {
           result += 1;
           break;
       if (i + 1 !== result) {
         return false;
     return true;
   };
   const b = ['merge','reset','reset']
   console.log(b.isSubsetOf(['reset','merge','add','commit']));
   const a = ['commit','push','blame'];
   console.log(a.isSubsetOf(['commit','rebase','push','blame']));
   

5. isSubsetOf(arr)

   Array.prototype.isSubsetOf = function (arr) {
     var subArr = this;
     var words = {};
     for (var i = 0; i < arr.length; i++) {
       if (!words[arr[i]]) {
         words[arr[i]] = true;
     for (var i = 0; i < subArr.length; i++) {
   ...
   

6. isSubsetOf(array)

   Array.prototype.isSubsetOf = function(array) {
     return this.reduce(function (acc, val) {
       if (acc) {
         return array.includes(val);
       return false;
     }, true)
   };
   

7. isSubsetOf(array)

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

8. isSubsetOf(array)

   Array.prototype.isSubsetOf = function(array) {
     var isSubset = true;
     if(this.forEach(function(element){
       if(!array.includes(element)){
         isSubset = false;
     }));
     return isSubset;
   };
   ...
   

9. 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;
   };
   ...