this code doesn't work

 var arr1 = ["a", "b", "c"];
 var arrayJoin=[];
arrayJoin.concat(arr1.filter(function (val) {
                    return val == "a";
    }));

console.log(arrayJoin);

this works fine

arrayJoin=arr1.filter(function (val) {
                    return val == "a";
    }));

any idea how to concat the filter array?

this code doesn't work

 var arr1 = ["a", "b", "c"];
 var arrayJoin=[];
arrayJoin.concat(arr1.filter(function (val) {
                    return val == "a";
    }));

console.log(arrayJoin);

this works fine

arrayJoin=arr1.filter(function (val) {
                    return val == "a";
    }));

any idea how to concat the filter array?

• javascript

• 3 Array.prototype.concat() [...]The concat() method is used to merge two or more arrays. This method does **not** change the existing arrays, but instead **returns a new** array.[...] – t.niese Commented Dec 14, 2016 at 20:47
• 1 Array.prototype.filter() returns a new Array, so what do you need concat for – DavidDomain Commented Dec 14, 2016 at 20:49
• this is one concat in a series – baaroz Commented Dec 14, 2016 at 20:51

1 Answer 1

What about

arrayJoin = arrayJoin.concat(arr1.filter(function (val) {
                    return val == "a";
    }));