如何使用 lodash 从对象中删除未定义和空值？

Question

I have a Javascript object like:

var my_object = { a:undefined, b:2, c:4, d:undefined };

How to remove all the undefined properties? False attributes should stay.

Answer 1

You can simply chain _.omit() with _.isUndefined and _.isNull compositions, and get the result with lazy evaluation.

Demo

var result = _(my_object).omit(_.isUndefined).omit(_.isNull).value();

Update March 14, 2016 :

As mentioned by dylants in the comment section, you should use the _.omitBy() function since it uses a predicate instead of a property. You should use this for lodash version 4.0.0 and above.

DEMO

var result = _(my_object).omitBy(_.isUndefined).omitBy(_.isNull).value();

Update June 1, 2016 :

As commented by Max Truxa , lodash already provided an alternative _.isNil , which checks for both null and undefined :

var result = _.omitBy(my_object, _.isNil);

Answer 2

If you want to remove all falsey values then the most compact way is:

For Lodash 4.x and later :

_.pickBy({ a: null, b: 1, c: undefined }, _.identity);
>> Object {b: 1}

For legacy Lodash 3.x:

_.pick(obj, _.identity);

_.pick({ a: null, b: 1, c: undefined }, _.identity);
>> Object {b: 1}

Answer 3

The correct answer is:

_.omitBy({ a: null, b: 1, c: undefined, d: false }, _.isNil)

That results in:

{b: 1, d: false}

The alternative given here by other people:

_.pickBy({ a: null, b: 1, c: undefined, d: false }, _.identity);

Will remove also false values which is not desired here.

Answer 4

if you are using lodash, you can use _.compact(array) to remove all falsely values from an array.

_.compact([0, 1, false, 2, '', 3]);
// => [1, 2, 3]

https://lodash.com/docs/4.17.4#compact

Answer 5

To complete the other answers, in lodash 4 to ignore only undefined and null (And not properties like false ) you can use a predicate in _.pickBy :

_.pickBy(obj, v !== null && v !== undefined)

Example below :

 const obj = { a: undefined, b: 123, c: true, d: false, e: null}; const filteredObject = _.pickBy(obj, v => v !== null && v !== undefined); console.log = (obj) => document.write(JSON.stringify(filteredObject, null, 2)); console.log(filteredObject);

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.js"></script>

Answer 6

Just:

_.omit(my_object, _.isUndefined)

The above doesn't take in account null values, as they are missing from the original example and mentioned only in the subject, but I leave it as it is elegant and might have its uses.

Here is the complete example, less concise, but more complete.

var obj = { a: undefined, b: 2, c: 4, d: undefined, e: null, f: false, g: '', h: 0 };
console.log(_.omit(obj, function(v) { return _.isUndefined(v) || _.isNull(v); }));

Answer 7

According to lodash docs:

_.compact(_.map(array, fn))

Also you can filter out all nulls

Answer 8

For deep nested object you can use my snippet for lodash > 4

const removeObjectsWithNull = (obj) => {
    return _(obj)
      .pickBy(_.isObject) // get only objects
      .mapValues(removeObjectsWithNull) // call only for values as objects
      .assign(_.omitBy(obj, _.isObject)) // save back result that is not object
      .omitBy(_.isNil) // remove null and undefined from object
      .value(); // get value
};

Answer 9

I encountered a similar problem with removing undefined from an object (deeply), and found that if you are OK to convert your plain old object and use JSON, a quick and dirty helper function would look like this:

function stripUndefined(obj) {
  return JSON.parse(JSON.stringify(obj));
}

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#Description

"...If undefined, a function, or a symbol is encountered during conversion it is either omitted (when it is found in an object) or censored to null (when it is found in an array)."

Answer 10

with pure JavaScript: (although Object.entries is ES7, Object.assign is ES6; but equivalent ES5 uses Object.keys only should be also doable); also notice v != null checks for both null and undefined;

> var d = { a:undefined, b:2, c:0, d:undefined, e: null, f: 0.3, s: "", t: false };
undefined
> Object.entries(d)
    .filter(([ k, v ]) => (v != null))
    .reduce((acc, [k, v]) => Object.assign(acc, {[k]: v}), {})
{ b: 2, c: 0, f: 0.3, s: '', t: false }

Edit: this below is the version with ES5 Object.keys only: but generally with ES7 in Node v8 is pretty much enjoyable ;-)

> Object.keys(d)
    .filter(function(k) { return d[k] != null; })
    .reduce(function(acc, k) { acc[k] = d[k]; return acc; }, {});
{ b: 2, c: 0, f: 0.3, s: '', t: false }

Update in October 2017 : with Node v8 (since v8.3 or so) now it has object spreading construct:

> var d = { a:undefined, b:2, c:0, d:undefined,
    e: null, f: -0.0, s: "", t: false, inf: +Infinity, nan: NaN };
undefined
> Object.entries(d)
    .filter(([ k, v ]) => (v != null))
    .reduce((acc, [k, v]) => ({...acc, [k]: v}), {})
{ b: 2, c: 0, f: -0, s: '', t: false, inf: Infinity, nan: NaN }

or within one reduce only:

> Object.entries(d)
   .reduce((acc, [k, v]) => (v==null ? acc : {...acc, [k]: v}), {})
{ b: 2, c: 0, f: -0, s: '', t: false, inf: Infinity, nan: NaN }

Update: someone want recursive? isn't that hard either, just need an additional check of isObject, and recursively call itself:

> function isObject(o) {
    return Object.prototype.toString.call(o) === "[object Object]"; }
undefined
> function dropNullUndefined(d) {
    return Object.entries(d)
      .reduce((acc, [k, v]) => (
        v == null ? acc :
         {...acc, [k]: (isObject(v) ? dropNullUndefined(v) : v) }
      ), {});
  }
> dropNullUndefined({a: 3, b:null})
{ a: 3 }
> dropNullUndefined({a: 3, b:null, c: { d: 0, e: undefined }})
{ a: 3, c: { d: 0 } }

my conclusion: if pure Javascript can do, I would avoid any third party library dependencies:

Answer 11

Since some of you might have arrived at the question looking to specifically removing only undefined , you can use:

• a combination of Lodash methods

  _.omitBy(object, _.isUndefined)

• the rundef package, which removes only undefined properties

  rundef(object)

---

If you need to recursively remove undefined properties, the rundef package also has a recursive option.

rundef(object, false, true);

See the documentation for more details.

Answer 12

Here's the lodash approach I'd take:

_(my_object)
    .pairs()
    .reject(function(item) {
        return _.isUndefined(item[1]) ||
            _.isNull(item[1]);
    })
    .zipObject()
    .value()

The pairs() function turns the input object into an array of key/value arrays. You do this so that it's easier to use reject() to eliminate undefined and null values. After, you're left with pairs that weren't rejected, and these are input for zipObject() , which reconstructs your object for you.

Answer 13

Taking in account that undefined == null we can write as follows:

let collection = {
  a: undefined,
  b: 2,
  c: 4,
  d: null,
}

console.log(_.omit(collection, it => it == null))
// -> { b: 2, c: 4 }

JSBin example

Answer 14

pickBy默认使用身份：

_.pickBy({ a: null, b: 1, c: undefined, d: false });

Answer 15

I like using _.pickBy, because you have full control over what you are removing:

var person = {"name":"bill","age":21,"sex":undefined,"height":null};

var cleanPerson = _.pickBy(person, function(value, key) {
  return !(value === undefined || value === null);
});

Source: https://www.codegrepper.com/?search_term=lodash+remove+undefined+values+from+object

Answer 16

最短的方式（lodash v4）：

_.pickBy(my_object)

Answer 17

从对象中删除未定义、空和空字符串

_.omitBy(object, (v) => _.isUndefined(v) || _.isNull(v) || v === '');

Answer 18

With lodash (or underscore) You may do

var my_object = { a:undefined, b:2, c:4, d:undefined, e:null };

var passedKeys = _.reject(Object.keys(my_object), function(key){ return _.isUndefined(my_object[key]) || _.isNull(my_object[key]) })

newObject = {};
_.each(passedKeys, function(key){
    newObject[key] = my_object[key];
});

Otherwise, with vanilla JavaScript, you can do

var my_object = { a:undefined, b:2, c:4, d:undefined };
var new_object = {};

Object.keys(my_object).forEach(function(key){
    if (typeof my_object[key] != 'undefined' && my_object[key]!=null){
        new_object[key] = my_object[key];
    }
});

Not to use a falsey test, because not only "undefined" or "null" will be rejected , also is other falsey value like "false", "0", empty string, {}. Thus, just to make it simple and understandable, I opted to use explicit comparison as coded above.

Answer 19

To omit all falsey values but keep the boolean primitives this solution helps.

_.omitBy(fields, v => (_.isBoolean(v)||_.isFinite(v)) ? false : _.isEmpty(v));

 let fields = { str: 'CAD', numberStr: '123', number : 123, boolStrT: 'true', boolStrF: 'false', boolFalse : false, boolTrue : true, undef: undefined, nul: null, emptyStr: '', array: [1,2,3], emptyArr: [] }; let nobj = _.omitBy(fields, v => (_.isBoolean(v)||_.isFinite(v)) ? false : _.isEmpty(v)); console.log(nobj);

 <script src="https://cdn.jsdelivr.net/npm/lodash@4.17.11/lodash.min.js"></script>

Answer 20

var my_object = { a:undefined, b:2, c:4, d:undefined };

var newObject = _.reject(my_collection, function(val){ return _.isUndefined(val) })

//--> newCollection = { b: 2, c: 4 }

Answer 21

I would use underscore and take care of empty strings too:

 var my_object = { a:undefined, b:2, c:4, d:undefined, k: null, p: false, s: '', z: 0 }; var result =_.omit(my_object, function(value) { return _.isUndefined(value) || _.isNull(value) || value === ''; }); console.log(result); //Object {b: 2, c: 4, p: false, z: 0}

jsbin .

Answer 22

For deep nested object and arrays. and exclude empty values from string and NaN

function isBlank(value) {
  return _.isEmpty(value) && !_.isNumber(value) || _.isNaN(value);
}
var removeObjectsWithNull = (obj) => {
  return _(obj).pickBy(_.isObject)
    .mapValues(removeObjectsWithNull)
    .assign(_.omitBy(obj, _.isObject))
    .assign(_.omitBy(obj, _.isArray))
    .omitBy(_.isNil).omitBy(isBlank)
    .value();
}
var obj = {
  teste: undefined,
  nullV: null,
  x: 10,
  name: 'Maria Sophia Moura',
  a: null,
  b: '',
  c: {
    a: [{
      n: 'Gleidson',
      i: 248
    }, {
      t: 'Marta'
    }],
    g: 'Teste',
    eager: {
      p: 'Palavra'
    }
  }
}
removeObjectsWithNull(obj)

result:

{
   "c": {
      "a": [
         {
            "n": "Gleidson",
            "i": 248
         },
         {
            "t": "Marta"
         }
      ],
      "g": "Teste",
      "eager": {
         "p": "Palavra"
      }
   },
   "x": 10,
   "name": "Maria Sophia Moura"
}

Answer 23

For those of you getting here looking to remove from an array of objects and using lodash you can do something like this:

 const objects = [{ a: 'string', b: false, c: 'string', d: undefined }]
 const result = objects.map(({ a, b, c, d }) => _.pickBy({ a,b,c,d }, _.identity))

 // [{ a: 'string', c: 'string' }]

Note: You don't have to destruct if you don't want to.

Answer 24

If you don't want to remove false values. Here is an example:

obj = {
  "a": null,
  "c": undefined,
  "d": "a",
  "e": false,
  "f": true
}
_.pickBy(obj, x => x === false || x)
> {
    "d": "a",
    "e": false,
    "f": true
  }

Answer 25

You can also use Object.entries with Array.prototype.filter .

const omitNullish = (object) => 
   Object.fromEntries(
       Object.entries(object).filter(([, value]) => value != null)
   )

omitNullish({ a: null, b: 1, c: undefined, d: false, e: 0 }) // { b: 1, d: false, e: 0}

If you want to use lodash, they are removing omit from v5 so an alternative is to use fp/pickBy along with isNil and negate .

import pickBy from 'lodash/fp/pickBy'
import isNil from 'lodash/isNil';
import negate from 'lodash/negate';


const omitNullish = pickBy(negate(isNil))

omitNullish({ a: null, b: 1, c: undefined, d: false, e: 0 }) // { b: 1, d: false, e: 0}

Answer 26

I was able to do this in deep objects that include arrays with just one lodash function, transform .

Note that the double-unequal (!= null) is intentional as it will also match undefined, as is the typeof 'object' check as it will match both object and array.

This is for use with plain data objects only that don't contain classes.

const cloneDeepSanitized = (obj) =>
  Array.isArray(obj)
    ? obj.filter((entry) => entry != null).map(cloneDeepSanitized)
    : transform(
        obj,
        (result, val, key) => {
          if (val != null) {
            result[key] =
              typeof val === 'object' ? cloneDeepSanitized(val) : val;
          }
        },
        {},
      );

Answer 27

You can use lodash to remove null and undefined objects , but you should konw what lodash method you need to use, many dev uses isNil to remove the Null and undefined objects , but this function not remove the empty objects (' ')

you can use isEmpty to remove Null , Undefined and

import pickBy from 'lodash/fp/pickBy'
import negate from 'lodash/negate';
import isEmpty from 'lodash/isEmpty';

const omitNullish = pickBy(negate(isEmpty));

      addressObject = {
      "a": null,
      "c": undefined,
      "d": "",
      "e": "test1",
      "f": "test2
    }

 const notNullObjects = omitNullish(addressObject);
 
 console.log(notNullObjects); 

you will have this object : { "e": "test1", "f": "test2 }