feat: base

src/query.ts

@@ -1,20 +1,27 @@
+import * as _ from 'lodash';
 import { Data, Field } from './types';
 
 export class Query {
 
   private data;
+  private dataGroup;
+  private fileds;
 
   constructor(data: Data) {
     this.data = data;
+    this.dataGroup = { data };
+    this.fileds = [];
   }
 
   /**
    * 选择字段
    * @param fields 
    */
   public select(...fields: Field[]): Query {
-
-    // TODO
+    this.fileds = [
+      ...this.fileds,
+      ...fields,
+    ];
 
     return this;
   }
@@ -25,8 +32,14 @@ export class Query {
    * @param asc 
    */
   public orderBy(fields: string, asc?: boolean): Query {
-
-    // TODO
+    for (const fileds in this.dataGroup) {
+      if (typeof this.dataGroup[fields][0][fields] === 'number') {
+        this.dataGroup[fields].sort((item1, item2) => asc ? item1 > item2 : item1 < item2);
+      } else {
+        this.dataGroup[fields].sort();
+      }
+    }
+
 
     return this;
   }
@@ -37,8 +50,15 @@ export class Query {
    * @param fields 
    */
   public groupBy(fields: string): Query {
+    const tempMap = {};
+    this.data.forEach(item => {
+      if (!tempMap[item[fields]]) {
+        tempMap[item[fields]] = [];
+      }
+      tempMap[item[fields]].push(item);
+    })
 
-    // TODO
+    this.dataGroup = tempMap;
 
     return this;
   }
@@ -48,8 +68,10 @@ export class Query {
    * @param n 
    */
   public limit(n: number): Query {
-
-    // TODO
+    for (const fileds in this.dataGroup) {
+      const groupData = this.dataGroup[fileds];
+      this.dataGroup[fileds] = groupData.slice(0, n);
+    }
 
     return this;
   }
@@ -58,9 +80,21 @@ export class Query {
    * 返回最后的查询数据
    */
   public record(): Data {
+    const res = [];
+    for (const group of this.dataGroup.values()) {
+      const groupData = group.reduce((data, item) => {
+        const itemData = {};
+        for (const key in item) {
+          if (this.fileds.includes(key)) {
+            itemData[key] = item[key];
+          }
+        }
+        data.push(itemData);
+        return data;
+      }, []);
+      res.push(groupData);
+    }
 
-    // TODO
-
-    return [];
+    return res;
   }
-}
+}