从"Blog"仓库中分离出来

admin/src/app/utils/dataUtil.ts

@@ -0,0 +1,42 @@
+import {Page} from '../classes/page';
+import {Observable, of} from 'rxjs';
+
+/**
+ * 判断 一个Page<any>[] 中是否存在一条已查询的数据
+ * @param pageNum 页码
+ * @param pageSize 单页数量
+ * @param pageList 源数据
+ * @return 未查到：null  查到：该条数据
+ */
+export function exist<T>(pageNum: number, pageSize: number, pageList: Page<any>[]): Observable<Page<T>> {
+    if (pageList === undefined || pageList == null || pageList.length === 0) {
+        return null;
+    }
+    // tslint:disable-next-line:prefer-for-of
+    for (let i = 0; i < pageList.length; i++) {
+        // tslint:disable-next-line:triple-equals
+        if (pageList[i].pageNum == pageNum && pageList[i].pageSize == pageSize) {
+            return of<Page<T>>(pageList[i]);
+        }
+    }
+    return null;
+}
+
+
+/**
+ * 将reqBody对象 转化为拼接到url上面的字符串
+ * @param reqBody 请求体 from {a:xx,b:xxx}
+ * @return      字符串        to ==> a=xx&b=xxx
+ */
+export function reqBody2Str(reqBody: object): string {
+    let submitBody = '';
+    for (const key in reqBody) {
+        // 跳过值为null的参数请求
+        if (reqBody[key] == null || reqBody[key] === 'null') {
+            continue;
+        }
+        submitBody = submitBody + '&' + key + '=' + reqBody[key];
+    }
+    return submitBody.substring(1);
+}
+