I tried using isNaN(value) and !isNaN(value) but I am unable to remove the NaN element in the give code without removing the strings. (Obviously because string is not a number).
function cleaner(arr) {
return = arr.filter(function f(value) {return (value !== false && value !== null && value !== 0 && value !== undefined)});
}
cleaner([7, "eight", false, null, 0, undefined, NaN, 9, ""]);
The above code should return [7, "eight", 9, ""];
This will return only numbers (without 0) and strings (including empty ones).
function cleaner(arr) {
return arr.filter(function(item){
return typeof item == "string" || (typeof item == "number" && item);
/** Any string**/ /** Numbers without NaN & 0 **/
});
}
console.log(cleaner([7, "eight", false, null, 0, undefined, NaN, 9, ""]));
//[7, "eight", 9, ""]Using ES2015 Arrow Function syntax
array.filter(item => typeof item == "string" || (typeof item == "number" && item));
var filteredArr = [7, "eight", false, null, 0, undefined, NaN, 9, ""].filter(item => typeof item == "string" || (typeof item == "number" && !isNaN(item) && item));
console.log(filteredArr);
Some ways to detect whether x is NaN:
Number.isNaN(x) (ES6)Object.is(x, NaN) (ES6)x !== x(typeof x === 'number') && isNaN(x)Note: isNaN alone is not a reliable way to check if a value is NaN!
filter to remove some items from an array. He wants to remove NaNs too, but using !isNaN removed both NaN and strings. That's because isNaN is not a reliable way to check if a value is NaN. Or that's what I understood, at least.isNaN(value) and !isNaN(value) but I am unable to remove the NaN element in the give code without removing the strings".Since you want to filter out all falsy values except empty strings, all you need is
function cleaner(arr) {
return arr.filter(function(value) {
return value === '' || value;
});
}
If you had wanted to filter out all falsy values including empty strings, you could have done:
function cleaner(arr) {
return arr.filter(Boolean);
}
filter(function(value) { return isNaN(value); }) ) on the array [7, "eight", NaN,] returns ["eight", null]. I need it to return [7,"eight]..filter(Boolean); Boolean returns false on all 0, -0, null, false, NaN, undefined, and the empty string (""). I need it to return on some of these but not all.""). That's why it makes sense to simply list that single exception, as I have done in the answer above. The accepted answer has the unfortunate behavior that it removes all objects, arrays, functions, regexps, etc. etc., which may or may be what you want, but seems like a bug waiting to happen. Also it's long and ugly.
falseandnullandundefinedare notNaNs. OnlyNaNisNaNNaNs.typeofof thevalueis either astringor anumberand you're done.