fix: error without filterableColumns. Added logger (#381)

README.md

@@ -91,6 +91,12 @@ http://localhost:3000/cats?limit=5&page=2&sortBy=color:DESC&search=i&filter.age=
 }
 ```
 
+Array values for filter operators such as `$in` should be provided as comma-separated values:
+
+```
+http://localhost:3000/cats?filter.name=$in:George,Milo
+```
+
 #### Code
 
 ```ts
@@ -292,3 +298,10 @@ const config: PaginateConfig<CatEntity> = {
 
 const result = await paginate<CatEntity>(query, catRepo, config)
 ```
+
+## Troubleshooting
+
+The package does not report error reasons in the response bodies. They are instead
+reported as `debug` level [logging](https://docs.nestjs.com/techniques/logger#logger).
+
+Common errors include missing `sortableColumns` or `filterableColumns` (the latter only affects filtering).

src/paginate.ts

@@ -16,12 +16,14 @@ import {
     FindOptionsWhere,
 } from 'typeorm'
 import { PaginateQuery } from './decorator'
-import { ServiceUnavailableException } from '@nestjs/common'
+import { ServiceUnavailableException, Logger } from '@nestjs/common'
 import { values, mapKeys } from 'lodash'
 import { stringify } from 'querystring'
 import { WherePredicateOperator } from 'typeorm/query-builder/WhereClause'
 import { Column, Order, RelationColumn, SortBy } from './helper'
 
+const logger: Logger = new Logger('nestjs-paginate')
+
 export class Paginated<T> {
     data: T[]
     meta: {
@@ -119,11 +121,16 @@ export function getFilterTokens(raw: string): string[] {
 
 function parseFilter<T>(query: PaginateQuery, config: PaginateConfig<T>) {
     const filter: { [columnName: string]: FindOperator<string> } = {}
+    let filterableColumns = config.filterableColumns
+    if (filterableColumns === undefined) {
+        logger.debug("No 'filterableColumns' given, ignoring filters.")
+        filterableColumns = {}
+    }
     for (const column of Object.keys(query.filter)) {
-        if (!(column in config.filterableColumns)) {
+        if (!(column in filterableColumns)) {
             continue
         }
-        const allowedOperators = config.filterableColumns[column]
+        const allowedOperators = filterableColumns[column]
         const input = query.filter[column]
         const statements = !Array.isArray(input) ? [input] : input
         for (const raw of statements) {
@@ -197,7 +204,10 @@ export async function paginate<T>(
         return !!entityColumns.find((c) => c === column)
     }
 
-    if (config.sortableColumns.length < 1) throw new ServiceUnavailableException()
+    if (config.sortableColumns.length < 1) {
+        logger.debug("Missing required 'sortableColumns' config.")
+        throw new ServiceUnavailableException()
+    }
 
     if (query.sortBy) {
         for (const order of query.sortBy) {