背景 段階的に片付けしていく、というFlowのコンセプトで、最も需要が高いのは、純粋なJSで済む状態管理、 とくに Redux の Reducer の部分であると考えられる。 実際のコード とりあえずこうなるだろうというのを書いてみた。 /* @flow */ // constants const INCREMENT = 'increment' const ADD = 'add' export const Actions = { INCREMENT, ADD } // actions export type IncrementAction = { type: typeof Actions.INCREMENT } export type AddAction = { type: typeof Actions.ADD, payload: number } export type CounterA
![Flow & Redux で Reducer の実装パターンを考える - Qiita](https://cdn-ak-scissors.b.st-hatena.com/image/square/cb05fe211a233b30e72fcd2c11579a0e145c02cd/height=288;version=1;width=512/https%3A%2F%2Fqiita-user-contents.imgix.net%2Fhttps%253A%252F%252Fcdn.qiita.com%252Fassets%252Fpublic%252Farticle-ogp-background-412672c5f0600ab9a64263b751f1bc81.png%3Fixlib%3Drb-4.0.0%26w%3D1200%26mark64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-dGV4dD9peGxpYj1yYi00LjAuMCZ3PTk3MiZoPTM3OCZ0eHQ9RmxvdyUyMCUyNiUyMFJlZHV4JTIwJUUzJTgxJUE3JTIwUmVkdWNlciUyMCVFMyU4MSVBRSVFNSVBRSU5RiVFOCVBMyU4NSVFMyU4MyU5MSVFMyU4MiVCRiVFMyU4MyVCQyVFMyU4MyVCMyVFMyU4MiU5MiVFOCU4MCU4MyVFMyU4MSU4OCVFMyU4MiU4QiZ0eHQtYWxpZ249bGVmdCUyQ3RvcCZ0eHQtY29sb3I9JTIzMjEyMTIxJnR4dC1mb250PUhpcmFnaW5vJTIwU2FucyUyMFc2JnR4dC1zaXplPTU2JnM9Y2I5Y2M5OTg4ODQ4MTllOGUwZDdhOGQwYTIwYmZlZmI%26mark-x%3D142%26mark-y%3D57%26blend64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-dGV4dD9peGxpYj1yYi00LjAuMCZoPTc2Jnc9NzcwJnR4dD0lNDBtaXpjaGkmdHh0LWNvbG9yPSUyMzIxMjEyMSZ0eHQtZm9udD1IaXJhZ2lubyUyMFNhbnMlMjBXNiZ0eHQtc2l6ZT0zNiZ0eHQtYWxpZ249bGVmdCUyQ3RvcCZzPTM3NjdjNDAyYWFiOGYxMDdjNTcxNTJiZjU0ODYyN2Rh%26blend-x%3D142%26blend-y%3D436%26blend-mode%3Dnormal%26txt64%3DaW4g5qCq5byP5Lya56S-44OX44Os44Kk44OJ%26txt-width%3D770%26txt-clip%3Dend%252Cellipsis%26txt-color%3D%2523212121%26txt-font%3DHiragino%2520Sans%2520W6%26txt-size%3D36%26txt-x%3D156%26txt-y%3D536%26s%3Dd6b5d345bc913b0db1fbd45d894c566b)