Set all Object keys to false

Question

Lets say I have an object

  filter: {
    "ID": false,
    "Name": true,
    "Role": false,
    "Sector": true,
    "Code": false
  }

I want to set all keys to false (to reset them). What's the best way to do this, I'd like to avoid looping with foreach and stuff. Any neat one liner?

Answer 1

Using lodash, mapValues is a graceful, loop-free way:

filter = {
    "ID": false,
    "Name": true,
    "Role": false,
    "Sector": true,
    "Code": false
};

filter = _.mapValues(filter, () => false);

If you want to do this with Underscore.js, there is an equivalent, but with a slightly different name:

filter = _.mapObject(filter, () => false);

In either case, the value of filter will be set to:

{ ID: false, 
  Name: false, 
  Role: false, 
  Sector: false, 
  Code: false }

Answer 2

Well here's a one-liner with vanilla JS:

Object.keys(filter).forEach(v => filter[v] = false)

It does use an implicit loop with the .forEach() method, but you'd have to loop one way or another (unless you reset by replacing the whole object with a hardcoded default object literal).

Answer 3

If you're not using ES6, here is it's ES5 counterpart.

Object.keys(filter).forEach(function(key, value) {
    return filter[key] = false;
})

Answer 4

hasOwnProperty must be used

```

for(var i in your_object) {
  if (Object.hasOwnProperty.call(your_object, i)) {
    your_object[i] = false;
  }
}

```

Answer 5

A small line of code compatible with all browsers:

for(var i in your_object) your_object[i] = false;

Answer 6

In case you are dealing with 'scope' variables, this might be a better solution.

Object.keys(filter).reduce(function(accObj, parseObj) {
                accObj[parseObj] = false;
                return accObj;
              }, {});

Answer 7

With ES6 features one-liner without mutation:

{
  ...Object.keys(filter).reduce((reduced, key) => ({ ...reduced, [key]: false }), {})
}