datatable query helper

src/utils/datatable.ts

@@ -0,0 +1,65 @@
+import { Knex } from "knex";
+import { db } from "@db/db";
+
+export interface RequestQuery {
+    length: string;
+    start: string;
+    order: { column: string; dir: string }[];
+    columns: { [key: string]: { data: string; searchable: string } };
+    search: { value: string };
+}
+
+export interface ResponseQuery {
+    query: Knex.QueryBuilder;
+    recordsTotal: number | string;
+    recordsFiltered: number | string;
+}
+
+export const buildDatatableQuery = async (request: { query: RequestQuery }, tableName: string): Promise<ResponseQuery> => {
+    const size: number = parseInt(request.query.length) || 10;
+    const start: number = parseInt(request.query.start);
+    const order: string = (
+        request.query.order && request.query.columns
+        [request.query.order[0].column].data
+    ) || 'id'
+    const direction: string = (request.query.order && request.query.order[0].dir) || "asc";
+    const search: string = request.query.search.value;
+
+    let query = db(tableName);
+
+    if (search) {
+        console.log("applying search: " + search)
+        console.log("columns: " + JSON.stringify(request.query.columns, null, 4));
+        query = query.where(builder => {
+            Object.values(request.query.columns)
+                .filter(column => column.searchable === "true")
+                .forEach((col, index) =>
+                    index === 0
+                        ? builder.where(col.data, "like", `%${search}%`)
+                        : builder.orWhere(col.data, "like", `%${search}%`)
+                );
+        });
+        console.log(query.toSQL());
+        // Object.keys(request.query.columns).forEach(key => {
+        //     const column = request.query.columns[key];
+        //     console.log(JSON.stringify(column));
+        //     if (column.searchable === "true") {
+        //         query = query.where(column.data, "like", `%${search}%`);
+        //     }
+        // })
+    }
+
+    const recordsTotalResult = await db(tableName).count("* as count").first();
+    const recordsTotal = recordsTotalResult ? recordsTotalResult.count : 0;
+
+    const recordsFilteredResult = await query.clone().count("* as count").first();
+    const recordsFiltered = recordsFilteredResult ? recordsFilteredResult.count : 0;
+
+    query = query.orderBy(order, direction).limit(size).offset(start);
+
+    return {
+        query,
+        recordsTotal,
+        recordsFiltered
+    };
+}