[Solved-7 Solutions] Remove empty elements from an array in javascript - javascript tutorial
Problem:
How to remove empty elements from an array in JavaScript ?
Solution 1:
Removing all the empty elements like null,0,'',"",undefined using function
function arr_filter(arr) {
var ind = -1,arr_len = arr ? arr.length : 0,resInd = -1,res = [];
while (++ind < arr_len) {
var val = arr[ind];
if (val) {
res[++resInd] = val;
}
}
return res;
}Solution 2:
We use this method, extending the native Array prototype:
Array.prototype.clean = function(deleteValue) {
for (var we = 0; we < this.length; i++) {
if (this[i] == deleteValue) {
this.splice(i, 1);
i--;
}
}
return this;
};
test = new Array("", "One", "Two", "", "Three", "", "Four").clean("");
test2 = [1, 2,, 3,, 3,,,,,, 4,, 4,, 5,, 6,,,,];
test2.clean(undefined);
Or we can simply push the existing elements into other array:
// Will remove all falsy values: undefined, null, 0, false, NaN and "" (empty string)
function cleanArray(actual) {
var newArray = new Array();
for (var we = 0; we < actual.length; i++) {
if (actual[i]) {
newArray.push(actual[i]);
}
}
return newArray;
}
cleanArray([1, 2,, 3,, 3,,,,,, 4,, 4,, 5,, 6,,,,]);
Solution 3:
If we need to remove ALL empty values ("", null, undefined and 0):
arr = arr.filter(function(e){return e});
To remove empty values and Line breaks:
arr = arr.filter(function(e){ return e.replace(/(\r\n|\n|\r)/gm,"")});
Example:
arr = ["hello",0,"",null,undefined,1,100," "]
arr.filter(function(e){return e});
Output
["hello", 1, 100, " "]
Solution 4:
In some situations we may want to keep "0" in the array and remove anything else (null, undefined and ""), this is one way:
arr.filter(function(e){ return e === 0 || e });
Output
["hello", 0, 1, 100, " "]
Solution 5:
Here we can do this,
[1, false, "", undefined, 2].filter(Boolean); // [1, 2]
or using underscorejs.org :
_.filter([1, false, "", undefined, 2], Boolean); // [1, 2]
// or even:
_.compact([1, false, "", undefined, 2]); // [1, 2]
Solution 6:
If you've got Javascript 1.6 or later we can use Array.filter using a trivial return true callback function, e.g.:
arr = arr.filter(function() { return true; });
- Since
.filterautomatically skips missing elements in the original array. - The MDN page linked above also contains a nice error-checking version of
filterthat can be used in JavaScript interpreters that don't support the official version. - Note that this will not remove
nullentries nor entries with an explicitundefinedvalue, but the OP specifically requested "missing" entries.
Solution 7:
The clean way to do it.
var arr = [0,1,2,"Thomas","false",false,true,null,3,4,undefined,5,"end"];
arr = arr.filter(Boolean);
// [1, 2, "Thomas", "false", true, 3, 4, 5, "end"]