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Feature request: encourage Enumerable#filter_map #178

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ghiculescu opened this issue Oct 8, 2020 · 1 comment · Fixed by #211
Closed

Feature request: encourage Enumerable#filter_map #178

ghiculescu opened this issue Oct 8, 2020 · 1 comment · Fixed by #211

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@ghiculescu
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https://blog.saeloun.com/2019/05/25/ruby-2-7-enumerable-filter-map.html

This was introduced in ruby 2.7. It adds a modest speedup over .map {}.compact or .select {}.map {}.
@ghiculescu ghiculescu changed the title Add Enumerable#filter_map Feature request: encourage Enumerable#filter_map Oct 8, 2020
@koic
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koic commented Oct 14, 2020

This is a note about an incompatibility between filter_map and compact. filter_map excludes false unlike compact.

[true, false, nil].compact              #=> [true, false]
[true, false, nil].filter_map(&:itself) #=> [true]

koic added a commit to koic/rubocop-performance that referenced this issue Feb 9, 2021
@koic
[Fix rubocop#178] Add new Performance/FilterMap cop
bd31073 
Fixes rubocop#178.

This PR adds new `Performance/FilterMap` cop.

In Ruby 2.7, `Enumerable#filter_map` has been added.

This cop identifies places where `select.map` can be replaced by `filter_map`.
And it allows `map { ... }.compact` that is not compatible with `filter_map`.

```ruby
[true, false, nil].compact              #=> [true, false]
[true, false, nil].filter_map(&:itself) #=> [true]
```

The following is good and bad cases.

```ruby
# bad
ary.select(&:foo).map(&:bar)
ary.filter(&:foo).map(&:bar)

# good
ary.filter_map { |o| o.bar if o.foo }
ary.map(&:foo).compact # Consider #whether you can safely replace it with `filter_map`.
```
@koic koic mentioned this issue Feb 9, 2021
Merged
8 tasks
koic added a commit to koic/rubocop-performance that referenced this issue Feb 9, 2021
@koic
[Fix rubocop#178] Add new Performance/FilterMap cop
11d3c61 
Fixes rubocop#178.

This PR adds new `Performance/FilterMap` cop.

In Ruby 2.7, `Enumerable#filter_map` has been added.

This cop identifies places where `select.map` can be replaced by `filter_map`.
And it allows `map { ... }.compact` that is not compatible with `filter_map`.

```ruby
[true, false, nil].compact              #=> [true, false]
[true, false, nil].filter_map(&:itself) #=> [true]
```

The following is good and bad cases.

```ruby
# bad
ary.select(&:foo).map(&:bar)
ary.filter(&:foo).map(&:bar)

# good
ary.filter_map { |o| o.bar if o.foo }
ary.map(&:foo).compact # Consider whether you can safely replace it with `filter_map`.
```
koic added a commit to koic/rubocop-performance that referenced this issue Feb 10, 2021
@koic
[Fix rubocop#178] Add new Performance/FilterMap cop
28d7d76 
Fixes rubocop#178.

This PR adds new `Performance/FilterMap` cop.

In Ruby 2.7, `Enumerable#filter_map` has been added.

This cop identifies places where `select.map` can be replaced by `filter_map`.
And it allows `map { ... }.compact` that is not compatible with `filter_map`.

```ruby
[true, false, nil].compact              #=> [true, false]
[true, false, nil].filter_map(&:itself) #=> [true]
```

The following is good and bad cases.

```ruby
# bad
ary.select(&:foo).map(&:bar)
ary.filter(&:foo).map(&:bar)

# good
ary.filter_map { |o| o.bar if o.foo }
ary.map(&:foo).compact # Consider whether you can safely replace it with `filter_map`.
```
koic added a commit to koic/rubocop-performance that referenced this issue Feb 10, 2021
@koic
[Fix rubocop#178] Add new Performance/FilterMap cop
2751929 
Fixes rubocop#178.

This PR adds new `Performance/FilterMap` cop.

In Ruby 2.7, `Enumerable#filter_map` has been added.

This cop identifies places where `select.map` can be replaced by `filter_map`.
And it allows `map { ... }.compact` that is not compatible with `filter_map`.

```ruby
[true, false, nil].compact              #=> [true, false]
[true, false, nil].filter_map(&:itself) #=> [true]
```

The following is good and bad cases.

```ruby
# bad
ary.select(&:foo).map(&:bar)
ary.filter(&:foo).map(&:bar)

# good
ary.filter_map { |o| o.bar if o.foo }
ary.map(&:foo).compact # Consider whether you can safely replace it with `filter_map`.
```
koic added a commit to koic/rubocop-performance that referenced this issue Feb 17, 2021
@koic
[Fix rubocop#178] Add new Performance/FilterMap cop
28b6369 
Fixes rubocop#178 and rubocop#193.

This PR adds new `Performance/FilterMap` cop.

In Ruby 2.7, `Enumerable#filter_map` has been added.

This cop identifies places where `select.map` can be replaced by `filter_map`.
And it allows `map { ... }.compact` that is not compatible with `filter_map`.

```ruby
[true, false, nil].compact              #=> [true, false]
[true, false, nil].filter_map(&:itself) #=> [true]
```

The following is good and bad cases.

```ruby
# bad
ary.select(&:foo).map(&:bar)
ary.filter(&:foo).map(&:bar)

# good
ary.filter_map { |o| o.bar if o.foo }
ary.map(&:foo).compact # Consider whether you can safely replace it with `filter_map`.
```
koic added a commit to koic/rubocop-performance that referenced this issue Apr 12, 2021
@koic
[Fix rubocop#178] Add new Performance/SelectMap cop
f31af62 
Fixes rubocop#178 and rubocop#193.

This PR adds new `Performance/SelectMap` cop.

In Ruby 2.7, `Enumerable#filter_map` has been added.

This cop identifies places where `select.map` can be replaced by `filter_map`.

The following is good and bad cases.

```ruby
# bad
ary.select(&:foo).map(&:bar)
ary.filter(&:foo).map(&:bar)

# good
ary.filter_map { |o| o.bar if o.foo }
```
koic added a commit to koic/rubocop-performance that referenced this issue Apr 17, 2021
@koic
[Fix rubocop#178] Add new Performance/SelectMap cop
f267ffe 
Fixes rubocop#178 and rubocop#193.

This PR adds new `Performance/SelectMap` cop.

In Ruby 2.7, `Enumerable#filter_map` has been added.

This cop identifies places where `select.map` can be replaced by `filter_map`.

The following is good and bad cases.

```ruby
# bad
ary.select(&:foo).map(&:bar)
ary.filter(&:foo).map(&:bar)

# good
ary.filter_map { |o| o.bar if o.foo }
```
@koic koic closed this as completed in #211 Apr 18, 2021
koic added a commit that referenced this issue Apr 18, 2021
@koic
Merge pull request #211 from koic/add_new_performance_filter_map_cop
6c5c8e3 
[Fix #178] Add new `Performance/SelectMap` cop
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[Fix #178] Add new Performance/SelectMap cop koic/rubocop-performance
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@koic @ghiculescu