'Remove blank attributes from an Object in Javascript
How do I remove all attributes which are undefined or null in a JavaScript object?
(Question is similar to this one for Arrays)
Solution 1:[1]
ES10/ES2019 examples
A simple one-liner (returning a new object).
let o = Object.fromEntries(Object.entries(obj).filter(([_, v]) => v != null));
Same as above but written as a function.
function removeEmpty(obj) {
return Object.fromEntries(Object.entries(obj).filter(([_, v]) => v != null));
}
This function uses recursion to remove items from nested objects.
function removeEmpty(obj) {
return Object.fromEntries(
Object.entries(obj)
.filter(([_, v]) => v != null)
.map(([k, v]) => [k, v === Object(v) ? removeEmpty(v) : v])
);
}
ES6/ES2015 examples
A simple one-liner. Warning: This mutates the given object instead of returning a new one.
Object.keys(obj).forEach((k) => obj[k] == null && delete obj[k]);
A single declaration (not mutating the given object).
let o = Object.keys(obj)
.filter((k) => obj[k] != null)
.reduce((a, k) => ({ ...a, [k]: obj[k] }), {});
Same as above but written as a function.
function removeEmpty(obj) {
return Object.entries(obj)
.filter(([_, v]) => v != null)
.reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {});
}
This function uses recursion to remove items from nested objects.
function removeEmpty(obj) {
return Object.entries(obj)
.filter(([_, v]) => v != null)
.reduce(
(acc, [k, v]) => ({ ...acc, [k]: v === Object(v) ? removeEmpty(v) : v }),
{}
);
}
Same as the function above, but written in an imperative (non-functional) style.
function removeEmpty(obj) {
const newObj = {};
Object.entries(obj).forEach(([k, v]) => {
if (v === Object(v)) {
newObj[k] = removeEmpty(v);
} else if (v != null) {
newObj[k] = obj[k];
}
});
return newObj;
}
ES5/ES2009 examples
In the old days things were a lot more verbose.
This is a non recursive version written in a functional style.
function removeEmpty(obj) {
return Object.keys(obj)
.filter(function (k) {
return obj[k] != null;
})
.reduce(function (acc, k) {
acc[k] = obj[k];
return acc;
}, {});
}
This is a non recursive version written in an imperative style.
function removeEmpty(obj) {
const newObj = {};
Object.keys(obj).forEach(function (k) {
if (obj[k] && typeof obj[k] === "object") {
newObj[k] = removeEmpty(obj[k]);
} else if (obj[k] != null) {
newObj[k] = obj[k];
}
});
return newObj;
}
And a recursive version written in a functional style.
function removeEmpty(obj) {
return Object.keys(obj)
.filter(function (k) {
return obj[k] != null;
})
.reduce(function (acc, k) {
acc[k] = typeof obj[k] === "object" ? removeEmpty(obj[k]) : obj[k];
return acc;
}, {});
}
Solution 2:[2]
Shortest one liners for ES6+
Filter all falsy values ( "", 0, false, null, undefined )
Object.entries(obj).reduce((a,[k,v]) => (v ? (a[k]=v, a) : a), {})
Filter null and undefined values:
Object.entries(obj).reduce((a,[k,v]) => (v == null ? a : (a[k]=v, a)), {})
Filter ONLY null
Object.entries(obj).reduce((a,[k,v]) => (v === null ? a : (a[k]=v, a)), {})
Filter ONLY undefined
Object.entries(obj).reduce((a,[k,v]) => (v === undefined ? a : (a[k]=v, a)), {})
Recursive Solutions: Filters null and undefined
For Objects:
const cleanEmpty = obj => Object.entries(obj)
.map(([k,v])=>[k,v && typeof v === "object" ? cleanEmpty(v) : v])
.reduce((a,[k,v]) => (v == null ? a : (a[k]=v, a)), {});
For Objects and Arrays:
const cleanEmpty = obj => {
if (Array.isArray(obj)) {
return obj
.map(v => (v && typeof v === 'object') ? cleanEmpty(v) : v)
.filter(v => !(v == null));
} else {
return Object.entries(obj)
.map(([k, v]) => [k, v && typeof v === 'object' ? cleanEmpty(v) : v])
.reduce((a, [k, v]) => (v == null ? a : (a[k]=v, a)), {});
}
}
Solution 3:[3]
If you are using lodash or underscore.js, here is a simple solution:
var obj = {name: 'John', age: null};
var compacted = _.pickBy(obj);
This will only work with lodash 4, pre lodash 4 or underscore.js, use _.pick(obj, _.identity);
Solution 4:[4]
If somebody needs a recursive version of Owen's (and Eric's) answer, here it is:
/**
* Delete all null (or undefined) properties from an object.
* Set 'recurse' to true if you also want to delete properties in nested objects.
*/
function delete_null_properties(test, recurse) {
for (var i in test) {
if (test[i] === null) {
delete test[i];
} else if (recurse && typeof test[i] === 'object') {
delete_null_properties(test[i], recurse);
}
}
}
Solution 5:[5]
JSON.stringify removes the undefined keys.
removeUndefined = function(json){
return JSON.parse(JSON.stringify(json))
}
Solution 6:[6]
You can use a combination of JSON.stringify, its replacer parameter, and JSON.parse to turn it back into an object. Using this method also means the replacement is done to all nested keys within nested objects.
Example Object
var exampleObject = {
string: 'value',
emptyString: '',
integer: 0,
nullValue: null,
array: [1, 2, 3],
object: {
string: 'value',
emptyString: '',
integer: 0,
nullValue: null,
array: [1, 2, 3]
},
arrayOfObjects: [
{
string: 'value',
emptyString: '',
integer: 0,
nullValue: null,
array: [1, 2, 3]
},
{
string: 'value',
emptyString: '',
integer: 0,
nullValue: null,
array: [1, 2, 3]
}
]
};
Replacer Function
function replaceUndefinedOrNull(key, value) {
if (value === null || value === undefined) {
return undefined;
}
return value;
}
Clean the Object
exampleObject = JSON.stringify(exampleObject, replaceUndefinedOrNull);
exampleObject = JSON.parse(exampleObject);
Solution 7:[7]
Simplest possible Lodash solution to return an object with the null and undefined values filtered out.
_.omitBy(obj, _.isNil)
Solution 8:[8]
You are probably looking for the delete keyword.
var obj = { };
obj.theProperty = 1;
delete obj.theProperty;
Solution 9:[9]
You can do a recursive removal in one line using json.stringify's replacer argument
const removeEmptyValues = obj => (
JSON.parse(JSON.stringify(obj, (k,v) => v ?? undefined))
)
Usage:
removeEmptyValues({a:{x:1,y:null,z:undefined}}) // Returns {a:{x:1}}
As mentioned in Emmanuel's comment, this technique only worked if your data structure contains only data types that can be put into JSON format (strings, numbers, lists, etc).
(This answer has been updated to use the new Nullish Coalescing operator. depending on browser support needs you may want to use this function instead: (k,v) => v!=null ? v : undefined)
Solution 10:[10]
you can do shorter with ! condition
var r = {a: null, b: undefined, c:1};
for(var k in r)
if(!r[k]) delete r[k];
Remember in usage : as @semicolor announce in comments: This would also delete properties if the value is an empty string, false or zero
Solution 11:[11]
I have same scenario in my project and achieved using following method.
It works with all data types, few mentioned above doesn't work with date and empty arrays .
removeEmptyKeysFromObject.js
removeEmptyKeysFromObject(obj) {
Object.keys(obj).forEach(key => {
if (Object.prototype.toString.call(obj[key]) === '[object Date]' && (obj[key].toString().length === 0 || obj[key].toString() === 'Invalid Date')) {
delete obj[key];
} else if (obj[key] && typeof obj[key] === 'object') {
this.removeEmptyKeysFromObject(obj[key]);
} else if (obj[key] == null || obj[key] === '') {
delete obj[key];
}
if (obj[key]
&& typeof obj[key] === 'object'
&& Object.keys(obj[key]).length === 0
&& Object.prototype.toString.call(obj[key]) !== '[object Date]') {
delete obj[key];
}
});
return obj;
}pass any object to this function removeEmptyKeysFromObject()
Solution 12:[12]
Using ramda#pickBy you will remove all null, undefined and false values:
const obj = {a:1, b: undefined, c: null, d: 1}
R.pickBy(R.identity, obj)
As @manroe pointed out, to keep false values use isNil():
const obj = {a:1, b: undefined, c: null, d: 1, e: false}
R.pickBy(v => !R.isNil(v), obj)
Solution 13:[13]
Remove all the properties with null and undefined
let obj = {
"id": 1,
"firstName": null,
"lastName": null,
"address": undefined,
"role": "customer",
"photo": "fb79fd5d-06c9-4097-8fdc-6cebf73fab26/fc8efe82-2af4-4c81-bde7-8d2f9dd7994a.jpg",
"location": null,
"idNumber": null,
};
let result = Object.entries(obj).reduce((a,[k,v]) => (v == null ? a : (a[k]=v, a)), {});
console.log(result)Solution 14:[14]
Shorter ES6 pure solution, convert it to an array, use the filter function and convert it back to an object. Would also be easy to make a function...
Btw. with this .length > 0 i check if there is an empty string / array, so it will remove empty keys.
const MY_OBJECT = { f: 'te', a: [] }
Object.keys(MY_OBJECT)
.filter(f => !!MY_OBJECT[f] && MY_OBJECT[f].length > 0)
.reduce((r, i) => { r[i] = MY_OBJECT[i]; return r; }, {});
Solution 15:[15]
Functional and immutable approach, without .filter and without creating more objects than needed
Object.keys(obj).reduce((acc, key) => (obj[key] === undefined ? acc : {...acc, [key]: obj[key]}), {})
Solution 16:[16]
Instead of delete the property, you can also create a new object with the keys that are not null.
const removeEmpty = (obj) => {
return Object.keys(obj).filter(key => obj[key]).reduce(
(newObj, key) => {
newObj[key] = obj[key]
return newObj
}, {}
)
}
Solution 17:[17]
For a deep search I used the following code, maybe it will be useful for anyone looking at this question (it is not usable for cyclic dependencies ) :
function removeEmptyValues(obj) {
for (var propName in obj) {
if (!obj[propName] || obj[propName].length === 0) {
delete obj[propName];
} else if (typeof obj[propName] === 'object') {
removeEmptyValues(obj[propName]);
}
}
return obj;
}
Solution 18:[18]
If you want 4 lines of a pure ES7 solution:
const clean = e => e instanceof Object ? Object.entries(e).reduce((o, [k, v]) => {
if (typeof v === 'boolean' || v) o[k] = clean(v);
return o;
}, e instanceof Array ? [] : {}) : e;
Or if you prefer more readable version:
function filterEmpty(obj, [key, val]) {
if (typeof val === 'boolean' || val) {
obj[key] = clean(val)
};
return obj;
}
function clean(entry) {
if (entry instanceof Object) {
const type = entry instanceof Array ? [] : {};
const entries = Object.entries(entry);
return entries.reduce(filterEmpty, type);
}
return entry;
}
This will preserve boolean values and it will clean arrays too. It also preserves the original object by returning a cleaned copy.
Solution 19:[19]
If you don't want to mutate in place, but return a clone with the null/undefined removed, you could use the ES6 reduce function.
// Helper to remove undefined or null properties from an object
function removeEmpty(obj) {
// Protect against null/undefined object passed in
return Object.keys(obj || {}).reduce((x, k) => {
// Check for null or undefined
if (obj[k] != null) {
x[k] = obj[k];
}
return x;
}, {});
}
Solution 20:[20]
To piggypack on Ben's answer on how to solve this problem using lodash's _.pickBy, you can also solve this problem in the sister library: Underscore.js's _.pick.
var obj = {name: 'John', age: null};
var compacted = _.pick(obj, function(value) {
return value !== null && value !== undefined;
});
See: JSFiddle Example
Solution 21:[21]
a reduce helper can do the trick (without type checking) -
const cleanObj = Object.entries(objToClean).reduce((acc, [key, value]) => {
if (value) {
acc[key] = value;
}
return acc;
}, {});
Solution 22:[22]
Here is a comprehensive recursive function (originally based on the one by @chickens) that will:
- recursively remove what you tell it to
defaults=[undefined, null, '', NaN] - Correctly handle regular objects, arrays and Date objects
const cleanEmpty = function(obj, defaults = [undefined, null, NaN, '']) {
if (!defaults.length) return obj
if (defaults.includes(obj)) return
if (Array.isArray(obj))
return obj
.map(v => v && typeof v === 'object' ? cleanEmpty(v, defaults) : v)
.filter(v => !defaults.includes(v))
return Object.entries(obj).length
? Object.entries(obj)
.map(([k, v]) => ([k, v && typeof v === 'object' ? cleanEmpty(v, defaults) : v]))
.reduce((a, [k, v]) => (defaults.includes(v) ? a : { ...a, [k]: v}), {})
: obj
}
USAGE:
// based off the recursive cleanEmpty function by @chickens.
// This one can also handle Date objects correctly
// and has a defaults list for values you want stripped.
const cleanEmpty = function(obj, defaults = [undefined, null, NaN, '']) {
if (!defaults.length) return obj
if (defaults.includes(obj)) return
if (Array.isArray(obj))
return obj
.map(v => v && typeof v === 'object' ? cleanEmpty(v, defaults) : v)
.filter(v => !defaults.includes(v))
return Object.entries(obj).length
? Object.entries(obj)
.map(([k, v]) => ([k, v && typeof v === 'object' ? cleanEmpty(v, defaults) : v]))
.reduce((a, [k, v]) => (defaults.includes(v) ? a : { ...a, [k]: v}), {})
: obj
}
// testing
console.log('testing: undefined \n', cleanEmpty(undefined))
console.log('testing: null \n',cleanEmpty(null))
console.log('testing: NaN \n',cleanEmpty(NaN))
console.log('testing: empty string \n',cleanEmpty(''))
console.log('testing: empty array \n',cleanEmpty([]))
console.log('testing: date object \n',cleanEmpty(new Date(1589339052 * 1000)))
console.log('testing: nested empty arr \n',cleanEmpty({ 1: { 2 :null, 3: [] }}))
console.log('testing: comprehensive obj \n', cleanEmpty({
a: 5,
b: 0,
c: undefined,
d: {
e: null,
f: [{
a: undefined,
b: new Date(),
c: ''
}]
},
g: NaN,
h: null
}))
console.log('testing: different defaults \n', cleanEmpty({
a: 5,
b: 0,
c: undefined,
d: {
e: null,
f: [{
a: undefined,
b: '',
c: new Date()
}]
},
g: [0, 1, 2, 3, 4],
h: '',
}, [undefined, null]))Solution 23:[23]
Here's an alternative
Typescript:
function objectDefined <T>(obj: T): T {
const acc: Partial<T> = {};
for (const key in obj) {
if (obj[key] !== undefined) acc[key] = obj[key];
}
return acc as T;
}
Javascript:
function objectDefined(obj) {
const acc = {};
for (const key in obj) {
if (obj[key] !== undefined) acc[key] = obj[key];
}
return acc;
}
Solution 24:[24]
If someone needs to remove undefined values from an object with deep search using lodash then here is the code that I'm using. It's quite simple to modify it to remove all empty values (null/undefined).
function omitUndefinedDeep(obj) {
return _.reduce(obj, function(result, value, key) {
if (_.isObject(value)) {
result[key] = omitUndefinedDeep(value);
}
else if (!_.isUndefined(value)) {
result[key] = value;
}
return result;
}, {});
}
Solution 25:[25]
With Lodash:
_.omitBy({a: 1, b: null}, (v) => !v)
Solution 26:[26]
If you use eslint and want to avoid tripping the the no-param-reassign rule, you can use Object.assign in conjunction with .reduce and a computed property name for a fairly elegant ES6 solution:
const queryParams = { a: 'a', b: 'b', c: 'c', d: undefined, e: null, f: '', g: 0 };
const cleanParams = Object.keys(queryParams)
.filter(key => queryParams[key] != null)
.reduce((acc, key) => Object.assign(acc, { [key]: queryParams[key] }), {});
// { a: 'a', b: 'b', c: 'c', f: '', g: 0 }
Solution 27:[27]
Here is a functional way to remove nulls from an Object using ES6 without mutating the object using only reduce:
const stripNulls = (obj) => {
return Object.keys(obj).reduce((acc, current) => {
if (obj[current] !== null) {
return { ...acc, [current]: obj[current] }
}
return acc
}, {})
}
Solution 28:[28]
If you're okay with using Lodash, you can add the DeepDash recursive library and achieve what you want with some pretty concise code:
const prune = obj => _.filterDeep(obj, (v) => !(_.isUndefined(v) || _.isNull(v)));
Calling prune(anObjectWithNulls) will return the object without undefined or null values.
Solution 29:[29]
You can also use ...spread syntax using forEach something like this:
let obj = { a: 1, b: "b", c: undefined, d: null };
let cleanObj = {};
Object.keys(obj).forEach(val => {
const newVal = obj[val];
cleanObj = newVal ? { ...cleanObj, [val]: newVal } : cleanObj;
});
console.info(cleanObj);
Sources
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Source: Stack Overflow