---
title: "Rails 6.1 adds *_previously_was attribute methods"
description:
  "Rails 6.1 adds *_previously_was attribute methods for dirty tracking"
canonical_url: "https://www.bigbinary.com/blog/rails-6-1-adds-_previously_was-attribute-methods"
markdown_url: "https://www.bigbinary.com/blog/rails-6-1-adds-_previously_was-attribute-methods.md"
---

# Rails 6.1 adds \*\_previously_was attribute methods

Rails 6.1 adds \*\_previously_was attribute methods for dirty tracking

- Author: Abhay Nikam
- Published: December 3, 2019
- Categories: Rails 6.1, Rails

Rails 6.1 adds [\*\_previously_was](https://github.com/rails/rails/pull/36836)
attribute methods for dirty tracking the previous attribute value after the
model is saved or reset. `*_previously_was` returns the previous attribute value
that was changed before the model was saved

Before Rails 6.1, to retrieve the previous attribute value, we used
`*_previous_change` or
[previous_changes](https://apidock.com/rails/ActiveModel/Dirty/previous_changes).

Here is how it can be used.

#### Rails 6.0.0

```ruby
>> user = User.new
=> #<User id: nil, name: nil, email: nil, created_at: nil, updated_at: nil>

>> user.name = "Sam"

# *_was returns the original value. In this example, the name was initially nil.
>> user.name_was
=> nil
>> user.save!

# After save, the original value is set to "Sam". To retrieve the
# previous value, we had to use `previous_changes`.
>> user.previous_changes[:name]
=> [nil, "Sam"]
```

#### Rails 6.1.0

```ruby
>> user = User.find_by(name: "Sam")
=> #<User id: 1, name: "Sam", email: nil, created_at: "2019-10-14 17:53:06", updated_at: "2019-10-14 17:53:06">

>> user.name = "Nick"
>> user.name_was
=> "Sam"

>> user.save!

>> user.previous_changes[:name]
=> ["Sam", "Nick"]

# *_previously_was returns the previous value.
>> user.name_previously_was
=> "Sam"

# After reload, all the dirty tracking
# attributes is reset.
>> user.reload
>> user.name_previously_was
=> nil
```

Check out the [pull request](https://github.com/rails/rails/pull/36836) for more
details on this.

## Links

- [Human page](https://www.bigbinary.com/blog/rails-6-1-adds-_previously_was-attribute-methods)