Remove empty elements from an array in Javascript
How do I remove empty elements from an array in JavaScript?
Is there a straightforward way, or do I need to loop through it and remove them manually?
I use this method, extending the native Array prototype:
Array.prototype.clean = function(deleteValue) {
for (var i = 0; i < 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 you 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 i = 0; i < actual.length; i++) {
if (actual[i]) {
newArray.push(actual[i]);
}
}
return newArray;
}
cleanArray([1, 2,, 3,, 3,,,,,, 4,, 4,, 5,, 6,,,,]);
Simple ways:
var arr = [1,2,,3,,3,null,,0,,undefined,4,,4,,5,,6,,,,];
// (filter - JS 1.6 and above)
arr = arr.filter(function(n){ return n != undefined });
arr // [1, 2, 3, 3, 0, 4, 4, 5, 6]
//or - (only for arrays items which are numbers is numbers' strings)**
arr = arr.filter(Number) // [1, 3, 3, 4, 4, 5, 6]
// ES6 style (Firefox FTW)
arr.filter(n => true) // [1, 2, 3, 3, null, 0, undefined, 4, 4, 5, 6]
// or if "null" values are to be removed:
arr.filter(n => n)
or - (only for single array items of type "text")
['','1','2',3,,'4',,undefined,,,'5'].join('').split('');
// output: ["1","2","3","4","5"]
or - Classic way: simple iteration
var arr = [1,2,null, undefined,3,,3,,,0,,,[],,{},,5,,6,,,,],
len = arr.length, i;
for(i = 0; i < len; i++ )
arr[i] && arr.push(arr[i]); // copy non-empty values to the end of the array
arr.splice(0 , len); // cut the array and leave only the non-empty values
arr // [1,2,3,3,[],Object{},5,6]
via jQuery:
var arr = [1,2,,3,,3,,,0,,,4,,4,,5,,6,,,,];
arr = $.grep(arr,function(n){ return n == 0 || n });
arr // [1, 2, 3, 3, 0, 4, 4, 5, 6]
UPDATE - just another fast, cool way (using ES6):
var arr = [1,2,null, undefined,3,,3,,,0,,,4,,4,,5,,6,,,,],
temp = [];
for(let i of arr)
i && temp.push(i); // copy each non-empty value to the 'temp' array
arr = temp;
delete temp; // discard the variable
arr // [1, 2, 3, 3, 4, 4, 5, 6]
Remove empty values
['foo', '',, ' ', true, [], [1], {}, undefined].filter(String)
// ["foo", " ", true, [1], Object {}, undefined]
Remove falsely values
Another method that removes the "falsey" values of empty string "" , 0 and undefined
[1, 2,, 3,, 3,undefined,,"",false,null,0,NaN, 4," ", 4,true, 5,, 6,,,,].filter(Boolean);
// [1, 2, 3, 3, 4, " ", 4, true, 5, 6]
If you 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(/(rn|n|r)/gm,"")});
Example:
arr = ["hello",0,"",null,undefined,1,100," "]
arr.filter(function(e){return e});
Return:
["hello", 1, 100, " "]
UPDATE (based on Alnitak's comment)
In some situations you 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 });
Return:
["hello", 0, 1, 100, " "]
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