Introduce
First, the emoji search application is one of the basic examples of reactjs, you can see here https://github.com/ahfarmer/emoji-search
This article I have rewritten this application, along with applying Recoiljs in state management
Emoji Search application
First, to manage the state with Recoil, I will have to create atoms
src / Atoms / searchInput.js
1 2 3 4 5 6 7 8 | <span class="token keyword">import</span> <span class="token punctuation">{</span> atom <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">"recoil"</span> <span class="token punctuation">;</span> <span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token function">atom</span> <span class="token punctuation">(</span> <span class="token punctuation">{</span> key <span class="token punctuation">:</span> <span class="token string">"searchInputState"</span> <span class="token punctuation">,</span> <span class="token keyword">default</span> <span class="token punctuation">:</span> <span class="token string">""</span> <span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> |
src / Atoms / emojiList.js
1 2 3 4 5 6 7 8 9 10 11 12 | <span class="token keyword">import</span> <span class="token punctuation">{</span> selector <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">"recoil"</span> <span class="token punctuation">;</span> <span class="token keyword">import</span> <span class="token punctuation">{</span> getEmojiList <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">"../common"</span> <span class="token punctuation">;</span> <span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token function">selector</span> <span class="token punctuation">(</span> <span class="token punctuation">{</span> key <span class="token punctuation">:</span> <span class="token string">"emojiListSelector"</span> <span class="token punctuation">,</span> <span class="token keyword">get</span> <span class="token punctuation">:</span> <span class="token keyword">async</span> <span class="token punctuation">(</span> <span class="token punctuation">{</span> <span class="token keyword">get</span> <span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">{</span> <span class="token keyword">const</span> emojiList <span class="token operator">=</span> <span class="token keyword">await</span> <span class="token function">getEmojiList</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token keyword">return</span> emojiList <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> |
This app I just need 2 basic atoms, searchInput used when searching emoji, emojiList to save data. For the emojiList I want to use the atomFamily function, but for some reason I can’t use it
Once you have the atom, you can use the selector to “process” the data you need.
src / Selectors / filteredEmojiList.js
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | <span class="token keyword">import</span> <span class="token punctuation">{</span> selector <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">"recoil"</span> <span class="token punctuation">;</span> <span class="token keyword">import</span> searchInputAtom <span class="token keyword">from</span> <span class="token string">"../Atoms/searchInput"</span> <span class="token punctuation">;</span> <span class="token keyword">import</span> emojiListAtom <span class="token keyword">from</span> <span class="token string">"../Atoms/emojiList"</span> <span class="token punctuation">;</span> <span class="token keyword">import</span> <span class="token punctuation">{</span> filterEmoji <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">"../common"</span> <span class="token punctuation">;</span> <span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token function">selector</span> <span class="token punctuation">(</span> <span class="token punctuation">{</span> key <span class="token punctuation">:</span> <span class="token string">"filteredEmojiListSelector"</span> <span class="token punctuation">,</span> <span class="token keyword">get</span> <span class="token punctuation">:</span> <span class="token keyword">async</span> <span class="token punctuation">(</span> <span class="token punctuation">{</span> <span class="token keyword">get</span> <span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">{</span> <span class="token keyword">const</span> searchText <span class="token operator">=</span> <span class="token keyword">get</span> <span class="token punctuation">(</span> searchInputAtom <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token keyword">const</span> emojiList <span class="token operator">=</span> <span class="token keyword">get</span> <span class="token punctuation">(</span> emojiListAtom <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token keyword">return</span> <span class="token function">filterEmoji</span> <span class="token punctuation">(</span> emojiList <span class="token punctuation">,</span> searchText <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> |
src / common.js
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | <span class="token keyword">export</span> <span class="token keyword">async</span> <span class="token keyword">function</span> <span class="token function">getEmojiList</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">const</span> response <span class="token operator">=</span> <span class="token keyword">await</span> <span class="token function">fetch</span> <span class="token punctuation">(</span> <span class="token string">"/emojiList.json"</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token keyword">return</span> response <span class="token punctuation">.</span> <span class="token function">json</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">export</span> <span class="token keyword">function</span> <span class="token function">filterEmoji</span> <span class="token punctuation">(</span> emojiList <span class="token punctuation">,</span> text <span class="token punctuation">,</span> maxResult <span class="token operator">=</span> <span class="token number">100</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> emojiList <span class="token punctuation">.</span> <span class="token function">filter</span> <span class="token punctuation">(</span> emoji <span class="token operator">=></span> <span class="token punctuation">{</span> <span class="token keyword">if</span> <span class="token punctuation">(</span> emoji <span class="token punctuation">.</span> title <span class="token punctuation">.</span> <span class="token function">toLowerCase</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">.</span> <span class="token function">includes</span> <span class="token punctuation">(</span> text <span class="token punctuation">.</span> <span class="token function">toLowerCase</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> <span class="token boolean">true</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">if</span> <span class="token punctuation">(</span> emoji <span class="token punctuation">.</span> keywords <span class="token punctuation">.</span> <span class="token function">includes</span> <span class="token punctuation">(</span> text <span class="token punctuation">.</span> <span class="token function">toLowerCase</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> <span class="token boolean">true</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token keyword">return</span> <span class="token boolean">false</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token punctuation">.</span> <span class="token function">slice</span> <span class="token punctuation">(</span> <span class="token number">0</span> <span class="token punctuation">,</span> maxResult <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> |
Now I just need to render the data to the UI again.
src / App.js
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | <span class="token keyword">import</span> React <span class="token keyword">from</span> <span class="token string">"react"</span> <span class="token punctuation">;</span> <span class="token keyword">import</span> <span class="token punctuation">{</span> RecoilRoot <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">"recoil"</span> <span class="token punctuation">;</span> <span class="token keyword">import</span> Emoji <span class="token keyword">from</span> <span class="token string">"./Components/Emoji"</span> <span class="token punctuation">;</span> <span class="token keyword">import</span> <span class="token string">"./styles.css"</span> <span class="token punctuation">;</span> <span class="token keyword">export</span> <span class="token keyword">default</span> <span class="token keyword">function</span> <span class="token function">App</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span> <span class="token keyword">return</span> <span class="token punctuation">(</span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> RecoilRoot</span> <span class="token punctuation">></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> React.Suspense</span> <span class="token attr-name">fallback</span> <span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span> <span class="token punctuation">{</span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> div</span> <span class="token punctuation">></span></span> <span class="token plain-text">Loading...</span> <span class="token tag"><span class="token tag"><span class="token punctuation"></</span> div</span> <span class="token punctuation">></span></span> <span class="token punctuation">}</span></span> <span class="token punctuation">></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> Emoji</span> <span class="token punctuation">/></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"></</span> React.Suspense</span> <span class="token punctuation">></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"></</span> RecoilRoot</span> <span class="token punctuation">></span></span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> |
RecoilRoot will create a context so we can use other functions of Recoil . You should put it outside the App. React.Suspense is a feature of React still under development, but when you use Recoil, it will ask you to use this feature, when you fetch data can display the component instead.
Below is the Emoji component, which is easy to follow, so I wrote other components in the same file.
src / Components / Emoji.js
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 | <span class="token keyword">import</span> React <span class="token keyword">from</span> <span class="token string">"react"</span> <span class="token punctuation">;</span> <span class="token keyword">import</span> <span class="token punctuation">{</span> useRecoilValue <span class="token punctuation">,</span> useRecoilState <span class="token punctuation">}</span> <span class="token keyword">from</span> <span class="token string">"recoil"</span> <span class="token punctuation">;</span> <span class="token keyword">import</span> filteredEmojiList <span class="token keyword">from</span> <span class="token string">"../Selectors/filteredEmojiList"</span> <span class="token punctuation">;</span> <span class="token keyword">import</span> searchInput <span class="token keyword">from</span> <span class="token string">"../Atoms/searchInput"</span> <span class="token punctuation">;</span> <span class="token keyword">const</span> <span class="token function-variable function">Header</span> <span class="token operator">=</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">{</span> <span class="token keyword">const</span> <span class="token punctuation">[</span> text <span class="token punctuation">,</span> <span class="token keyword">set</span> <span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token function">useRecoilState</span> <span class="token punctuation">(</span> searchInput <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token keyword">const</span> <span class="token function-variable function">handleChange</span> <span class="token operator">=</span> e <span class="token operator">=></span> <span class="token punctuation">{</span> <span class="token keyword">set</span> <span class="token punctuation">(</span> e <span class="token punctuation">.</span> target <span class="token punctuation">.</span> value <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">;</span> <span class="token keyword">return</span> <span class="token punctuation">(</span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> div</span> <span class="token attr-name">className</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> Header <span class="token punctuation">"</span></span> <span class="token punctuation">></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> input</span> <span class="token attr-name">type</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> text <span class="token punctuation">"</span></span> <span class="token attr-name">placeholder</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> smile, angry,... <span class="token punctuation">"</span></span> <span class="token attr-name">value</span> <span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span> <span class="token punctuation">{</span> text <span class="token punctuation">}</span></span> <span class="token attr-name">onChange</span> <span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span> <span class="token punctuation">{</span> handleChange <span class="token punctuation">}</span></span> <span class="token attr-name">autoFocus</span> <span class="token punctuation">/></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"></</span> div</span> <span class="token punctuation">></span></span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">;</span> <span class="token keyword">const</span> <span class="token function-variable function">EmojiCard</span> <span class="token operator">=</span> <span class="token punctuation">(</span> <span class="token punctuation">{</span> title <span class="token punctuation">,</span> symbol <span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">{</span> <span class="token keyword">const</span> codePointHex <span class="token operator">=</span> symbol <span class="token punctuation">.</span> <span class="token function">codePointAt</span> <span class="token punctuation">(</span> <span class="token number">0</span> <span class="token punctuation">)</span> <span class="token punctuation">.</span> <span class="token function">toString</span> <span class="token punctuation">(</span> <span class="token number">16</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token keyword">const</span> src <span class="token operator">=</span> <span class="token template-string"><span class="token string">`//cdn.jsdelivr.net/emojione/assets/png/</span> <span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span> codePointHex <span class="token interpolation-punctuation punctuation">}</span></span> <span class="token string">.png`</span></span> <span class="token punctuation">;</span> <span class="token keyword">return</span> <span class="token punctuation">(</span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> div</span> <span class="token attr-name">className</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> EmojiCard <span class="token punctuation">"</span></span> <span class="token punctuation">></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> img</span> <span class="token attr-name">alt</span> <span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span> <span class="token punctuation">{</span> title <span class="token punctuation">}</span></span> <span class="token attr-name">src</span> <span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span> <span class="token punctuation">{</span> src <span class="token punctuation">}</span></span> <span class="token punctuation">/></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> span</span> <span class="token attr-name">className</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> title <span class="token punctuation">"</span></span> <span class="token punctuation">></span></span> <span class="token punctuation">{</span> title <span class="token punctuation">}</span> <span class="token tag"><span class="token tag"><span class="token punctuation"></</span> span</span> <span class="token punctuation">></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"></</span> div</span> <span class="token punctuation">></span></span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">;</span> <span class="token keyword">const</span> <span class="token function-variable function">EmojiList</span> <span class="token operator">=</span> <span class="token punctuation">(</span> <span class="token punctuation">{</span> emojiList <span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">{</span> <span class="token keyword">const</span> nodes <span class="token operator">=</span> emojiList <span class="token punctuation">.</span> <span class="token function">map</span> <span class="token punctuation">(</span> <span class="token punctuation">(</span> emoji <span class="token punctuation">,</span> index <span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">{</span> <span class="token keyword">return</span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> EmojiCard</span> <span class="token spread"><span class="token punctuation">{</span> <span class="token punctuation">...</span> <span class="token attr-value">emoji</span> <span class="token punctuation">}</span></span> <span class="token attr-name">key</span> <span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span> <span class="token punctuation">{</span> index <span class="token punctuation">}</span></span> <span class="token punctuation">/></span></span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token keyword">return</span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> div</span> <span class="token attr-name">className</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> EmojiList <span class="token punctuation">"</span></span> <span class="token punctuation">></span></span> <span class="token punctuation">{</span> nodes <span class="token punctuation">}</span> <span class="token tag"><span class="token tag"><span class="token punctuation"></</span> div</span> <span class="token punctuation">></span></span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">;</span> <span class="token keyword">const</span> <span class="token function-variable function">Emoji</span> <span class="token operator">=</span> <span class="token punctuation">(</span> <span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">{</span> <span class="token keyword">const</span> emojiList <span class="token operator">=</span> <span class="token function">useRecoilValue</span> <span class="token punctuation">(</span> filteredEmojiList <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token keyword">return</span> <span class="token punctuation">(</span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> div</span> <span class="token attr-name">className</span> <span class="token attr-value"><span class="token punctuation">=</span> <span class="token punctuation">"</span> Emoji <span class="token punctuation">"</span></span> <span class="token punctuation">></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> Header</span> <span class="token punctuation">/></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"><</span> EmojiList</span> <span class="token attr-name">emojiList</span> <span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span> <span class="token punctuation">{</span> emojiList <span class="token punctuation">}</span></span> <span class="token punctuation">/></span></span> <span class="token tag"><span class="token tag"><span class="token punctuation"></</span> div</span> <span class="token punctuation">></span></span> <span class="token punctuation">)</span> <span class="token punctuation">;</span> <span class="token punctuation">}</span> <span class="token punctuation">;</span> <span class="token keyword">export</span> <span class="token keyword">default</span> Emoji <span class="token punctuation">;</span> |
You can see the hooks of Recoil: useRecoilValue and useRecoilState . These are all basic hooks, you can refer to here.
https://recoiljs.org/docs/api-reference/core/useRecoilState
Result
You can see the demo and the complete code of the application here: https://codesandbox.io/s/admiring-albattani-wm1f9
I quite like this library because it is easy to share the state, the syntax is also very concise and easy to understand. Maybe I will use it from now on instead of using React Context.