|
| 1 | +--- |
| 2 | +id: 2019-06-17-hello-reason-react-native |
| 3 | +title: Hello Reason React Native |
| 4 | +author: MoOx |
| 5 | +--- |
| 6 | + |
| 7 | +Today is a big day for the ReasonML community as we are releasing the fruits of |
| 8 | +a long effort started about 4 months ago. |
| 9 | + |
| 10 | +As more and more people were starting to use ReasonML on production apps using |
| 11 | +React Native, we wanted to make the BuckleScript bindings for React Native, |
| 12 | +known has `bs-react-native`, more accessible. This would have involved several |
| 13 | +breaking changes in order to simplify some APIs that have been designed with a |
| 14 | +high level of security in mind, but at some costs. The cost of being harder to |
| 15 | +start with (for newcomers to ReasonML) as well as the cost in terms of code size |
| 16 | +and performance. |
| 17 | + |
| 18 | +While some of us were thinking about some simplifications, some others, involved |
| 19 | +in Reason React incoming changes, directly started a new approach for this |
| 20 | +bindings, following |
| 21 | +[the zero-cost approach offered by reason-react 0.7.0](https://reasonml.github.io/reason-react/blog/2019/04/10/react-hooks). |
| 22 | + |
| 23 | +[CCA](https://www.cca.io) started this effort on what is now know as the new |
| 24 | +`reason-react-native` bindings, that eliminates a huge part of the additional |
| 25 | +JavaScript code produced by the bindings. |
| 26 | + |
| 27 | +## Zero-cost |
| 28 | + |
| 29 | +By zero-cost, we means zero additional cost. The JavaScript code BuckleScript |
| 30 | +produces using this bindings will most of the time directly hit React Native |
| 31 | +JavaScript code without creating an unnecessary abstraction above it 🙌. |
| 32 | + |
| 33 | +Here are some random examples: |
| 34 | + |
| 35 | +- [`bs-react-native` `View`](https://github.com/reason-react-native/reason-react-native/blob/958cd4e3a5ffa303304a0b2404cd53b5f49e649f/bs-react-native/src/components/ViewProps.bs.js) |
| 36 | + vs |
| 37 | + [`reason-react-native` `View`](https://github.com/reason-react-native/reason-react-native/blob/958cd4e3a5ffa303304a0b2404cd53b5f49e649f/reason-react-native/src/components/View.bs.js) |
| 38 | +- [`bs-react-native` `Style`](https://github.com/reason-react-native/reason-react-native/blob/958cd4e3a5ffa303304a0b2404cd53b5f49e649f/bs-react-native/src/style.bs.js) |
| 39 | + vs |
| 40 | + [`reason-react-native` `Style`](https://github.com/reason-react-native/reason-react-native/blob/958cd4e3a5ffa303304a0b2404cd53b5f49e649f/reason-react-native/src/apis/Style.bs.js) |
| 41 | +- [`bs-react-native` `Platform`](https://github.com/reason-react-native/reason-react-native/blob/958cd4e3a5ffa303304a0b2404cd53b5f49e649f/bs-react-native/src/platform.bs.js) |
| 42 | + vs |
| 43 | + [`reason-react-native` `Platform`](https://github.com/reason-react-native/reason-react-native/blob/958cd4e3a5ffa303304a0b2404cd53b5f49e649f/reason-react-native/src/apis/Platform.bs.js) |
| 44 | + |
| 45 | +Some modules are even empty or with some minor `require()` that can be |
| 46 | +themselves almost empty and easily removed by some JavaScript bundlers. |
| 47 | + |
| 48 | +How cool is that? |
| 49 | + |
| 50 | +## But why `reason-react-native` ? |
| 51 | + |
| 52 | +`bs-react-native` already had multiple breaking changes in the past and we |
| 53 | +didn't really want to offer a poor experience by creating a new release with |
| 54 | +tons of changes that won't be easy to codemod (or would require much more work |
| 55 | +from us). |
| 56 | + |
| 57 | +On top of that, `reason-react` latest release already added an important |
| 58 | +breaking change with |
| 59 | +[JSX 3](https://reasonml.github.io/reason-react/docs/en/jsx). |
| 60 | + |
| 61 | +That's why we had this idea about offering an easy and smooth transition by |
| 62 | +offering 2 packages to say goodbye to `bs-react-native` without pain. |
| 63 | + |
| 64 | +- `bs-react-native-jsx3-compat` (0.11.1) |
| 65 | +- `reason-react-native` |
| 66 | + ([0.60.0](/en/docs/install/#note-about-reason-react-native-version-number)) |
| 67 | + |
| 68 | +## Wait, what is `bs-react-native-jsx3-compat` ? |
| 69 | + |
| 70 | +`bs-react-native` is using JSX 2 so in order to use it with JSX 3 we would have |
| 71 | +to create an additional layer on top of the current bindings to offer both JSX 2 |
| 72 | +and 3 bindings. And since we wanted to do away with some current APIs of |
| 73 | +`bs-react-native` we started to think about a new approach. |
| 74 | + |
| 75 | +We knew that we wanted to: |
| 76 | + |
| 77 | +- offer to `bs-react-native` users a migration plan, so they can start very |
| 78 | + easily to use JSX 3 and new `reason-react` (so they can use hooks), |
| 79 | +- offer new `reason-react-native` bindings, more accessible and with a zero cost |
| 80 | + approach. |
| 81 | +- offer a smooth transition between these two packages so people can slowly |
| 82 | + upgrade their codebase without having to make an insane PR that switches from |
| 83 | + one to the other. |
| 84 | + |
| 85 | +We don't want your co-workers to hate you with a PR that comes directly from |
| 86 | +hell 😅. |
| 87 | + |
| 88 | +That's where we thought about offering `bs-react-native-jsx3-compat`. It's a |
| 89 | +package that has the same APIs `bs-react-native` has but that uses |
| 90 | +`reason-react-native` under the hood. |
| 91 | + |
| 92 | +**This means you will have to make a migration from JSX 2 to 3**. That's the |
| 93 | +only thing you will have to do, then with a single change from `bs-react-native` |
| 94 | +with `bs-react-native-jsx3-compat` in your `bs-dependencies` you will be ready |
| 95 | +to use hooks and directly benefit of (almost) zero-cost bindings! |
| 96 | + |
| 97 | +And since we care about you and don't want you to upgrade from JSX 2 to 3 by |
| 98 | +hand, we got you covered with a script made with love to help you with that. |
| 99 | + |
| 100 | +[You will find all the required instructions to migrate from `bs-react-native` to `bs-react-native-jsx3-compat` in our documentation](/en/docs/migration/jsx3/). |
| 101 | + |
| 102 | +## tl;dr |
| 103 | + |
| 104 | +- `bs-react-native` has now entered a frozen state and won't receive any upgrade |
| 105 | +- `bs-react-native-jsx3-compat` allows you to use existing code based on |
| 106 | + `bs-react-native` with `reason-react` 0.7.0 and JSX 3 |
| 107 | +- `reason-react-native` package contains the new bindings for React Native, that |
| 108 | + offers more accessible APIs and that is almost zero-cost |
| 109 | +- [We offer you an easy and smooth migration plan so you can start using `reason-react-native` and slowly say bye to `bs-react-native`](/en/docs/migration/jsx3/). |
| 110 | + |
| 111 | +## Thanks |
| 112 | + |
| 113 | +This required effort has been keeping us busy for weeks and wouldn't have been |
| 114 | +possible without the following people: |
| 115 | + |
| 116 | +- CCA team and especially [@cknitt](https://github.com/cknitt) for leading us to |
| 117 | + the right direction for the new zero-cost bindings and all the contributions |
| 118 | + that come with this move |
| 119 | +- [@sgny](https://github.com/sgny) for all his contributions to the new bindings |
| 120 | +- [@MoOx](https://github.com/MoOx) for leading the effort, the compat layer and |
| 121 | + the new website you are seeing here |
| 122 | +- [@bloodyowl](https://github.com/bloodyowl) for his magical |
| 123 | + [reason-react-compat](https://github.com/bloodyowl/reason-react-compat) layer |
| 124 | + and |
| 125 | + [the alternate JSX 3 upgrade path](https://bloodyowl.github.io/blog/2019-04-19-an-alternative-migration-path-for-reason-react/) |
| 126 | + that goes with it |
| 127 | +- all the people that helped us on Discord and GitHub in various code reviews |
| 128 | + and improvements like the react native template (thanks |
| 129 | + [@dawee](https://github.com/dawee)) |
| 130 | + |
| 131 | +## What's next? |
| 132 | + |
| 133 | +Now that `reason-react-native` is ready to be used and that our migration plan |
| 134 | +is usable, we will probably be focused on documentation as lots of APIs and |
| 135 | +Components need to be documented. We really want to offer the best developer |
| 136 | +experience possible and that's definitely part of it. |
| 137 | + |
| 138 | +👉Now it's time for you to check our |
| 139 | +[Getting Started with Reason React Native documentation](/en/docs/) |
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