过滤数组的交集（Javascript）

Question

I'm trying to write a function that finds arrays that are not common to both nested arrays. Also note the arrays will be pre-sorted.

var array1 = [ [1, 2, 3], [2, 3, 4] [5, 6, 7] ];
var array2 = [ [1, 2, 3], [2, 3, 4] [7, 8, 9] ];

For the above two arrays the function should return [5, 6, 7] and [7, 8, 9].

So far I've got:

        function arrayIntersection(array1, array2) {
            return array2.filter(function(values1) {
                return array2.indexOf(values1) === -1;
            });
        };

But it doesn't seem to be working. I'm guessing the indexOf() isn't doing a compares correctly. I'm trying to avoid using ES6 or polyfills.

Answer 1

First, you referenced the wrong array in your filter. To fix the comparison, you could turn the arrays to json. You will also need to run the filter against the second array and join the answers.:

 var array1 = [ [1, 2, 3], [2, 3, 4], [5, 6, 7] ]; var array2 = [ [1, 2, 3], [2, 3, 4], [7, 8, 9] ]; function arrayIntersection(input1, input2) { var input2NotInInput1 = input2.filter(function(values1) { return input1.map(function(val) { return JSON.stringify(val); }).indexOf(JSON.stringify(values1)) === -1; }); var input1NotInInput2 = input1.filter(function(values1) { return input2.map(function(val) { return JSON.stringify(val); }).indexOf(JSON.stringify(values1)) === -1; }); return input1NotInInput2 .concat( input2NotInInput1 ); }; console.log(arrayIntersection(array1, array2)); 

Answer 2

You can use the built in .every() and .filter() array methods to accomplish this task.

 var array1 = [ [1, 2, 3], [2, 3, 4], [5, 6, 7] ]; var array2 = [ [1, 2, 3], [2, 3, 4], [7, 8, 9] ]; function compareArrays(arr1, arr2) { if (arr1.length !== arr2.length) { return false; } else { return arr1.every(function(elem) { return arr2.indexOf(elem) > -1; }); } } function filterUnique(arr1, arr2) { return arr1.filter(function(elem) { return arr2.every(function(_elem) { return !compareArrays(_elem, elem); }); }); } function filterIntersection(arr1, arr2) { var uniqueToArr1 = filterUnique(arr1, arr2); var uniqueToArr2 = filterUnique(arr2, arr1); return [].concat(uniqueToArr1, uniqueToArr2); } console.log(filterIntersection(array1, array2)); 

Answer 3

It's not a best option but it works

 var ar1 = [ [1, 2, 3], [2, 3, 4], [5, 6, 7] ]; var ar2 = [ [1, 2, 3], [2, 3, 4], [7, 8, 9] ]; function arrayIntersection(array1, array2) { return array2.filter(function(values1) { return !array1.some(v => JSON.stringify(v) === JSON.stringify(values1)); }); }; var result = arrayIntersection(ar1, ar2); console.log(result);