add helpers

src/app.module.ts

@@ -1,14 +1,10 @@
 import { Module } from '@nestjs/common';
 
-import { AppController } from './app.controller';
-import { AppService } from './app.service';
 import { ContentModule } from './modules/content/content.module';
 import { CoreModule } from './modules/core/core.module';
 import { DatabaseModule } from './modules/database/database.module';
 
 @Module({
-    imports: [ContentModule, CoreModule, DatabaseModule],
-    controllers: [AppController],
-    providers: [AppService],
+    imports: [ContentModule, CoreModule.forRoot(), DatabaseModule],
 })
 export class AppModule {}

src/modules/core/core.module.ts

@@ -1,4 +1,13 @@
-import { Module } from '@nestjs/common';
+import { DynamicModule, Module } from '@nestjs/common';
 
 @Module({})
-export class CoreModule {}
+export class CoreModule {
+    static forRoot(): DynamicModule {
+        return {
+            module: CoreModule,
+            global: true,
+            providers: [],
+            exports: [],
+        };
+    }
+}

src/modules/core/helpers/index.ts

@@ -0,0 +1 @@
+export * from './utils';

src/modules/core/helpers/utils.ts

@@ -0,0 +1,34 @@
+import deepmerge from 'deepmerge';
+import { isNil } from 'lodash';
+
+export function toBoolean(value?: string | boolean): boolean {
+    if (isNil(value)) {
+        return false;
+    }
+    if (typeof value === 'boolean') {
+        return value;
+    }
+    try {
+        return JSON.parse(value.toLowerCase());
+    } catch (error) {
+        return value as unknown as boolean;
+    }
+}
+
+export function toNull(value?: string | null): string | null | undefined {
+    return value === null ? null : value;
+}
+
+export const deepMerge = <T, P>(
+    x: Partial<T>,
+    y: Partial<P>,
+    arrayMode: 'replace' | 'merge' = 'merge',
+) => {
+    const options: deepmerge.Options = {};
+    if (arrayMode === 'replace') {
+        options.arrayMerge = (_d, s, _o) => s;
+    } else if (arrayMode === 'merge') {
+        options.arrayMerge = (_d, s, _o) => Array.from(new Set([..._d, ...s]));
+    }
+    return deepmerge(x, y, options) as P extends T ? T : T & P;
+};

src/modules/database/types.ts

@@ -0,0 +1,23 @@
+import { ObjectLiteral, SelectQueryBuilder } from 'typeorm';
+
+export type QueryHook<Entity> = (
+    qb: SelectQueryBuilder<Entity>,
+) => Promise<SelectQueryBuilder<Entity>>;
+
+export interface PaginateMeta {
+    itemCount: number;
+    totalItems?: number;
+    perPage: number;
+    totalPages?: number;
+    currentPage: number;
+}
+
+export interface PaginateOptions {
+    page?: number;
+    limit?: number;
+}
+
+export interface PaginateReturn<E extends ObjectLiteral> {
+    meta: PaginateMeta;
+    items: E[];
+}