In JavaScript you have the nice .filter method to remove null or falsy values from arrays. So far I haven't been able to find a method to remove the same from JavaScript Objects.
Why would this be?
Currently you can create a function for arrays like :
function stripNulls(arr) {
return arr.filter(Boolean);
}
Is there a similar function that can be created for JS Objects, or is the way filter works not practical on JS Objects.
The answer to "can I do x to an object" (or an array for that matter) is usually "yes" and it frequently involves some form of reduce.
If you want to filter falsy values you could do something like this:
function filterFalsy(obj) {
return Object.keys(obj).reduce((acc, key) => {
if (obj[key]) {
acc[key] = obj[key]
}
return acc
}, {})
}
const testObj = {
a: 'test',
b: 321,
c: false
}
console.log(filterFalsy(testObj))This returns a new object without falsy values and leaves the existing object alone.
WARNING: There are better answers provided here. Also, thanks to comments made below user's should be warned using delete may provide suboptimal performance.
Filtering invalid values is a little more complex in objects. At face value this will do what you want:
var arr = [ 'apple', 43, false ];
var trueArr = arr.filter(Boolean);
console.log(trueArr);
var obj = { 'title': 'apple', 'id': 43, 'isOrange': false, 'test': 'asd' };
Object.keys(obj)
.filter(key => !obj[key])
.forEach(key => delete obj[key]);
console.log(obj);However, this will not iterate over child objects / functions. This logic also directly modifies the original object (which may or may not be desired).
That can easily changed by adding this logic to a function like so:
function removeFalseyProperties(obj) {
Object.keys(obj)
.filter(key => !obj[key])
.forEach(key => delete obj[key]);
return obj;
}
var testObj = { 'title': 'apple', 'id': 43, 'isOrange': false, 'test': 'asd' };
var trutheyObj = removeFalseyProperties(testObj);
console.log(trutheyObj);
delete!delete performance issues.If you have lodash installed in your project, you can simply use
import _ from 'lodash';
_.pickBy(obj, Boolean)
falsy values are 0, undefined, null, false, etc.
myArray
.map(item => {
// ...
})
// Get rid of bad values
.filter(Boolean);
By passing Boolean we can remove all the falsy values.
for...inloop is your only option