“filter”和“indexOf”在IE中的Array上不支持。这个怎么样:

var array1 = [1, 2, 3];
var array2 = [2, 3, 4, 5];

var intersection = [];
for (i in array1) {
    for (j in array2) {
        if (array1[i] == array2[j]) intersection.push(array1[i]);
    }
}

通过使用.pop而不是.shift可以提高@atk实现对原语排序数组的性能。

function intersect(array1, array2) {
   var result = [];
   // Don't destroy the original arrays
   var a = array1.slice(0);
   var b = array2.slice(0);
   var aLast = a.length - 1;
   var bLast = b.length - 1;
   while (aLast >= 0 && bLast >= 0) {
      if (a[aLast] > b[bLast] ) {
         a.pop();
         aLast--;
      } else if (a[aLast] < b[bLast] ){
         b.pop();
         bLast--;
      } else /* they're equal */ {
         result.push(a.pop());
         b.pop();
         aLast--;
         bLast--;
      }
   }
   return result;
}

我使用jsPerf创建了一个基准测试。使用。pop要快三倍。

如果只使用关联数组呢?

function intersect(a, b) {
    var d1 = {};
    var d2 = {};
    var results = [];
    for (var i = 0; i < a.length; i++) {
        d1[a[i]] = true;
    }
    for (var j = 0; j < b.length; j++) {
        d2[b[j]] = true;
    }
    for (var k in d1) {
        if (d2[k]) 
            results.push(k);
    }
    return results;
}

编辑:

// new version
function intersect(a, b) {
    var d = {};
    var results = [];
    for (var i = 0; i < b.length; i++) {
        d[b[i]] = true;
    }
    for (var j = 0; j < a.length; j++) {
        if (d[a[j]]) 
            results.push(a[j]);
    }
    return results;
}

function intersectionOfArrays(arr1, arr2) {
    return arr1.filter((element) => arr2.indexOf(element) !== -1).filter((element, pos, self) => self.indexOf(element) == pos);
}

破坏性似乎是最简单的，特别是如果我们可以假设输入是排序的:

/* destructively finds the intersection of 
 * two arrays in a simple fashion.  
 *
 * PARAMS
 *  a - first array, must already be sorted
 *  b - second array, must already be sorted
 *
 * NOTES
 *  State of input arrays is undefined when
 *  the function returns.  They should be 
 *  (prolly) be dumped.
 *
 *  Should have O(n) operations, where n is 
 *    n = MIN(a.length, b.length)
 */
function intersection_destructive(a, b)
{
  var result = [];
  while( a.length > 0 && b.length > 0 )
  {  
     if      (a[0] < b[0] ){ a.shift(); }
     else if (a[0] > b[0] ){ b.shift(); }
     else /* they're equal */
     {
       result.push(a.shift());
       b.shift();
     }
  }

  return result;
}

非破坏性的要稍微复杂一点，因为我们要跟踪指标:

/* finds the intersection of 
 * two arrays in a simple fashion.  
 *
 * PARAMS
 *  a - first array, must already be sorted
 *  b - second array, must already be sorted
 *
 * NOTES
 *
 *  Should have O(n) operations, where n is 
 *    n = MIN(a.length(), b.length())
 */
function intersect_safe(a, b)
{
  var ai=0, bi=0;
  var result = [];

  while( ai < a.length && bi < b.length )
  {
     if      (a[ai] < b[bi] ){ ai++; }
     else if (a[ai] > b[bi] ){ bi++; }
     else /* they're equal */
     {
       result.push(a[ai]);
       ai++;
       bi++;
     }
  }

  return result;
}

我会用对我来说最有效的方法来贡献:

if (!Array.prototype.intersect){
Array.prototype.intersect = function (arr1) {

    var r = [], o = {}, l = this.length, i, v;
    for (i = 0; i < l; i++) {
        o[this[i]] = true;
    }
    l = arr1.length;
    for (i = 0; i < l; i++) {
        v = arr1[i];
        if (v in o) {
            r.push(v);
        }
    }
    return r;
};
}