CODEWITHSUNDEEP
javascriptlodash
Ajay Srikanth
Ajay Srikanth

Reputation: 1185

delete unwanted properties from the javascript object

I have a javascript object like the one below with several fields and arrays and arrays within arrays. I'm only interested only in non-junk fields and wanted to remove all the junk properties from the objects. How can I do that using lodash?

I can do that by using delete, but I don't want to do that because that list is huge and I don't want to keep changing my code to write a delete every time a new junk property is added to my object.

{
 state: 'New York',
 country: 'usa',
 counties : [['washington','DC'],'Long Island',['New','Jersey']], 
 city : 'Manhattan',
 zip: '43543545',
 JunkOne : ['3453454','45345','45345'],
 JunkTwo: '5454545',
 JunkThree: {adc:'4545',vdfd:'45345'} 
}

Upvotes: 7

Views: 33330

Answers (8)

jay gajjar
jay gajjar

Reputation: 29

Better to use map with following function to extract only specific keys which you need

function extractKeyValuesFromObject(_obj, _keys) {
let result = {};
_keys.forEach(_k => result[_k] = _obj[_k]);
return result;

}

Upvotes: 0

Mike
Mike

Reputation: 2569

Disappointed that none of these answers solve the problem without making a new object (copy). I want something that works like _.set() that can delete at a path without causing an error when the path doesn't completely exist. Came up with this:

_.set(obj, 'path.to.property', null);
delete obj.path.to.property;

Upvotes: 0

Derek
Derek

Reputation: 1795

If you need some flexiblity in what to pick, lodash _.pickBy is really nice. For example:

const result = _.pickBy(someObject, function(value, key) {
  return key.search(/Junk/) == -1
});

If the function returns truthy, the key/value pair is picked from the object.

Upvotes: 0

guest271314
guest271314

Reputation: 1

You can use Object.keys(), RegExp /^Junk/ to check each property of object, call delete if match is found

var obj = {
 state: 'New York',
 country: 'usa',
 counties : [['washington','DC'],'Long Island',['New','Jersey']], 
 city : 'Manhattan',
 zip: '43543545',
 JunkOne : ['3453454','45345','45345'],
 JunkTwo: '5454545',
 JunkThree: {adc:'4545',vdfd:'45345'} 
};

var keys = Object.keys(obj);
var re = /^Junk/;
for (var i = 0; i < keys.length; i++) {
  if (re.test(keys[i])) {
   delete obj[keys[i]]
  }
}

console.log(obj)

Upvotes: 0

Nicolas Budig
Nicolas Budig

Reputation: 391

You can use lodash.pick() to create an object with only the requested keys. For example:

var city = {
  state: 'New York',
  country: 'usa',
  counties : [['washington','DC'],'Long Island',['New','Jersey']], 
  city : 'Manhattan',
  zip: '43543545',
  JunkOne : ['3453454','45345','45345'],
  JunkTwo: '5454545',
  JunkThree: {adc:'4545',vdfd:'45345'}
}
var lodash = require('lodash');
city = lodash.pick(city, ['state', 'country', 'counties','city','zip']);

City now should have all the useful data, and none of the junk.

Upvotes: 10

binariedMe
binariedMe

Reputation: 4329

use either delete operator to delete specific properties

delete data.JunkOne;

or use object.assign to select specific properties

var a = Object.assign({}, { counties: data.counties});

EDIT:

Doing it lodash way would be

var a = _.omit(data, ['JunkOne']);

or 

var a = _.pick(data, ['counties']);

Upvotes: 18

apsillers
apsillers

Reputation: 115940

You can use _.pick to create a new object with only a specific set of properties from your original object:

var objectWithNoJunk = _.pick(myObject, ['state', 'country', 'counties', 'city', 'zip']);

Upvotes: 7

Jared Smith
Jared Smith

Reputation: 21926

UPDATE

@aspillers answer is the same as mine but waaay shorter/better. Go with that.

var listOfGoodProps = [
  "city",
  "county",
  ...
];

Object.keys(yourObj).reduce(function(acc, key) {
  if (listOfGoodProps.indexOf(key) !== -1)
    acc[key] = yourObj[key];
  return acc;
}, {});

No lodash needed, straight up ES 5.

Upvotes: 2

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