[](https://github.com/byjord/MapRewire)
[](https://travis-ci.org/byjord/MapRewire)
[](https://coveralls.io/github/byjord/MapRewire)
[](https://libraries.io/hex/map_rewire)
Syntactic sugar to simply bulk rekey maps. MapRewire takes two arguments, data (map) and transformation (list of transformations / string of transformations separated by whitespace).
### Why did I do this?
Simply because I am super lazy, and writing out functions to take maps and convert them to different keys was boring (and irritating) the shit out of me.
IMHO rekeying maps with MapRewire is much nicer than having to write boilerplate like `defp from_x_to_y(data), do: %{ "another_id" => data["id"], "name" => data["title"] }`
### TL;DR; Syntax
1. Main Syntax: `left<~>right` (`content<~>transformation`). Left value is the map that holds the data and keys you would like to update, Right value is an Elixir List that contains a string for each of the keys that you would like to update.
2. Transformation Syntax: `left=>right` (`from=>to`). Left is the original key, right is the new key.
3. Return Syntax: `[left, right]` (`[ original, rekeyed ]`). `left` is the original map. `right` is the new, rekeyed, map.
## Getting started
### 1. Add as a dependency
```elixir
def deps do
[
{:map_rewire, "~> 0.1.1"}
]
end
```
### 2. Download
```bash
$ mix deps.get
```
### 3 (Optionally). Want to see inside MapRewire?
Add to config.exs
```elixir
config :map_rewire,
debug?: true
```
### 4. Run!
```bash
$ iex -S mix
```
## Usage
### Running in iex
**Example 1:** Inline example using a list transformation
```elixir
iex(1)> use MapRewire
iex(2)> %{"id"=>"234923409", "title"=>"asdf"}<~>["title=>name", "id=>shopify_id"]
[
%{"id" => "234923409", "title" => "asdf"},
%{"shopify_id" => "234923409", "name" => "asdf"}
]
```
**Example 2:** Inline example using a string transformation
```elixir
iex(1)> use MapRewire
iex(2)> %{"id"=>"234923409", "title"=>"asdf"}<~>"title=>name id=>shopify_id"
[
%{"id" => "234923409", "title" => "asdf"},
%{"shopify_id" => "234923409", "name" => "asdf"}
]
```
**Example 3:** Mixed example with a string transformation
```elixir
iex(1)> use MapRewire
iex(2)> content = %{
"id"=>"234923409",
"title"=>"asdf",
"body_html"=>"asdf"
}
iex(3)> content<~>"title=>name id=>shopify_id body_html=>desc no_match=>wow_much_field"
[
%{"id" => "234923409", "title" => "asdf", "body_html" => "asdf"},
%{"shopify_id" => "234923409", "name" => "asdf", "desc" => "asdf"}
]
```
**Example 4:** Dynamic example with a string transformation
```elixir
iex(1)> use MapRewire
iex(2)> content = %{
"id"=>"234923409",
"title"=>"asdf",
"body_html"=>"asdf"
}
iex(3)> transformation = "title=>name id=>shopify_id body_html=>desc no_match=>wow_much_field"
iex(4)> content<~>transformation
[
%{"id" => "234923409", "name" => "title", "body_html" => "asdf"},
%{"shopify_id" => "234923409", "name" => "asdf", "desc" => "asdf"}
]
```
**Example 5:** Dynamic example with a list transformation
```elixir
iex(1)> use MapRewire
iex(2)> content = %{
"id"=>"234923409",
"title"=>"asdf",
"body_html"=>"asdf"
}
iex(3)> transformation = ["title=>name", "id=>shopify_id", "body_html=>desc"]
iex(4)> content<~>transformation
[
%{"id" => "234923409", "name" => "asdf", "body_html" => "asdf"},
%{"shopify_id" => "234923409", "name" => "asdf", "desc" => "asdf"}
]
```
### Running as part of a module
**Example 1:**
```elixir
defmodule Foo do
use MapRewire
@becomes [
"id=>shopify_id",
"title=>name",
"body_html=>description"
]
def bar do
fake_factory
|> final
end
defp fake_factory do
%{
"id" => "234923409",
"title" => "asdf",
"body_html" => "asdfasdf"
}
end
def final(data) do
data<~>@becomes
end
end
```
Calling `Foo.bar()` will result in the output:
```elixir
[
%{"id" => "234923409", "title" => "asdf", "body_html" => "asdfasdf"},
%{"shopify_id" => "234923409", "name" => "asdf", "description" => "asdfasdf"}
]
```
**Example 2:**
```elixir
defmodule Foo do
use MapRewire
@becomes "age=>years_old languages=>technologies_known name=>this"
def bar do
fake_factory
|> final
end
defp fake_factory do
%{
"age"=> 31,
"languages"=> ["Erlang", "Ruby", "Elixir"],
"name"=> "John"
}
end
def final(data) do
data<~>@becomes
end
end
```
Calling `Foo.bar()` will result in the output:
```elixir
[
%{"age" => 31, "languages" => ["Erlang", "Ruby", "Elixir"], "name" => "John"},
%{"years_old" => 31, "technologies_known" => ["Erlang", "Ruby", "Elixir"], "this" => "John"}
]
```
