add helpers

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;
+};