└── README.md


/README.md:
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  1 | # Firestore 9 cookbook
  2 | 
  3 | 
  4 | #### Table of contents
  5 | - [Initialization](#initialization)
  6 | - [Read doc/docs](#read-doc-docs)
  7 |   * [Read collection](#read-collection)
  8 |   * [Read a single document](#read-a-single-document)
  9 |   * [Check a document exists or not](#check-a-document-exists-or-not)
 10 |   * [Conditionally querying data](#conditionally-querying-data)
 11 | - [Store data](#store-data)
 12 |   * [Store a doc with auto generated id](#store-a-doc-with-auto-generated-id)
 13 |   * [Store a doc with custom id](#store-a-doc-with-custom-id)
 14 | - [Deleting document](#deleting-document)
 15 |   * [Delete a document with id](#delete-a-document-with-id)
 16 | - [Update document](#update-document)
 17 | - [Sorting/limiting](#sorting-limiting)
 18 |   * [Get limited number of docs](#get-limited-number-of-docs)
 19 |   * [Limit with order](#limit-with-order)
 20 | 
 21 | 
 22 | 
 23 | 
 24 | 
 25 | ### Initialization
 26 | 
 27 | ```js
 28 | import { initializeApp } from "firebase/app";
 29 | import { getFirestore } from "firebase/firestore";
 30 | 
 31 | const config = {
 32 |   apiKey: "xxxx",
 33 |   authDomain: "xxxx",
 34 |   projectId: "xxxx",
 35 |   storageBucket: "xxxx",
 36 |   messagingSenderId: "xxxx",
 37 |   appId: "xxxx",
 38 | };
 39 | 
 40 | 
 41 | export const app = initializeApp(config);
 42 | export const db = getFirestore(app);
 43 | ```
 44 | 
 45 | 
 46 | ### Read doc/docs
 47 | 
 48 | #### Read collection
 49 | ```js
 50 | const collectionRef = collection(db, "users");
 51 | 
 52 | getDocs(collectionRef).then((snapshot) => {
 53 |   snapshot.docs.forEach((doc) => {
 54 |     console.log(doc.data());
 55 |   });
 56 | });
 57 | ```
 58 | 
 59 | #### Read a single document
 60 | ```js
 61 | const docRef = doc(db, "users", "G3OIFQ7qes9Rhc74XfRA");
 62 | // - OR
 63 | // const docRef = doc(db, "users/G3OIFQ7qes9Rhc74XfRA");
 64 | 
 65 | getDoc(docRef).then((snapshot) => {
 66 |   console.log(snapshot.data());
 67 | });
 68 | ```
 69 | 
 70 | #### Check a document exists or not
 71 | ```js
 72 | const docSnap = await getDoc(docRef);
 73 | 
 74 | if(!docSnap.exists()) {
 75 |   console.log("Document does not exist!");
 76 | }
 77 | ```
 78 | 
 79 | 
 80 | #### Conditionally querying data
 81 | ```js
 82 | const collectionRef = collection(db, "users");
 83 | const q = query(collectionRef, where("username", "==", "kingrayhan"));
 84 | 
 85 | const snapshot = await getDocs(q);
 86 | console.log(snapshot.docs[0].data());
 87 | 
 88 | 
 89 | 
 90 | 
 91 | 
 92 | // -- More query example
 93 | const stateQuery = query(citiesRef, where("state", "==", "CA"));
 94 | const populationQuery = query(citiesRef, where("population", "<", 100000));
 95 | const nameQuery = query(citiesRef, where("name", ">=", "San Francisco"));
 96 | ```
 97 | **Query operator**
 98 | - `<` - less than
 99 | - `<=` - less than or equal to
100 | - `==` - equal to
101 | - `>` - greater than
102 | - `>=` - greater than or equal to
103 | - `!=` - not equal to
104 | - `array-contains`
105 | - `array-contains-any`
106 | - `in`
107 | - `not-in`
108 | 
109 | 
110 | 
111 | ### Store data
112 | 
113 | #### Store a doc with auto generated id
114 | 
115 | ```js
116 | const collectionRef = collection(db, "users");
117 | const docRef = await addDoc(collectionRef, {
118 |   username: "johndoe",
119 |   avatar: "https://avatars0.githubusercontent.com/u/174825?v=4",
120 | });
121 | 
122 | console.log(docRef.id);
123 | ```
124 | 
125 | #### Store a doc with custom id
126 | 
127 | ```js
128 | const docRef = doc(db, "users", "user-id-custom");
129 | // - OR
130 | // const docRef = doc(db, "users/G3OIFQ7qes9Rhc74XfRA");
131 | 
132 | await setDoc(docRef, {
133 |   username: "kingrayhan",
134 |   avatar: "https://avatars0.githubusercontent.com/u/174825?v=4",
135 | });
136 | ```
137 | 
138 | ### Deleting document
139 | 
140 | #### Delete a document with id
141 | ```js
142 | const docRef = doc(db, "users", "xj7lxm0OGObV91xn3tE0");
143 | await deleteDoc(docRef);
144 | ```
145 | 
146 | ### Update document
147 | ```js
148 | const docRef = doc(db, "users", "AvPfqaJs4hCmqpk0RUjU");
149 | // - OR
150 | // const docRef = doc(db, "users/G3OIFQ7qes9Rhc74XfRA");
151 | 
152 | 
153 | /**
154 |  * Update document
155 |  */
156 | await updateDoc(docRef, {
157 |   name: "Rayhan",
158 |   username: "rayhan",
159 | });
160 | 
161 | /**
162 |  * Override the whole document
163 |  */
164 | await setDoc(docRef, {
165 |   x: 10,
166 | });
167 | ```
168 | 
169 | ### Sorting/limiting
170 | 
171 | #### Get limited number of docs
172 | ```js
173 | const colRef = collection(db, "posts");
174 | 
175 | const q = query(colRef, limit(5))
176 | const postsSnap = await getDocs(q)
177 | 
178 | const posts = postsSnap.docs.map((post) => post.data())
179 | 
180 | // -> console.log(posts)
181 | ```
182 | 
183 | #### Limit with order
184 | ```js
185 | const colRef = collection(db, "posts");
186 | 
187 | const q = query(colRef, limit(5), orderBy("createdAt", "desc"))
188 | const postsSnap = await getDocs(q)
189 | 
190 | const posts = postsSnap.docs.map((post) => post.data())
191 | 
192 | // -> console.log(posts)
193 | ```
194 | 


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