Add ability to specify custom conditionMapper

Author: perfectmak

src/index.js

@@ -90,7 +90,7 @@ export const splitColumnAndCondition = (filterQS) => {
   return { column, condition };
 };
 
-const processFilter = (filterQS, castFn, preprocessor) => {
+const processFilter = (filterQS, castFn, preprocessor, conditionMapper) => {
   const { column, condition } = splitColumnAndCondition(filterQS);
 
   const preprocessed = preprocessor(column);
@@ -105,7 +105,13 @@ const processFilter = (filterQS, castFn, preprocessor) => {
     if (cast) query = `(${preprocessed})::${cast}`;
   }
 
-  const currCondition = conditionMap[condition];
+  let currCondition = conditionMap[condition];
+  if (conditionMapper) {
+    const mappedCondition = conditionMapper(column, condition, currCondition);
+    if (mappedCondition) {
+      currCondition = mappedCondition;
+    }
+  }
   if (currCondition.includes('??')) {
     return currCondition.replace('??', query);
   }
@@ -116,13 +122,13 @@ const processFilter = (filterQS, castFn, preprocessor) => {
 
 export const knexFlexFilter = (originalQuery, where = {}, opts = {}) => {
   const {
-    castFn, preprocessor = defaultPreprocessor(), isAggregateFn, caseInsensitiveSearch = false,
+    castFn, preprocessor = defaultPreprocessor(), isAggregateFn, caseInsensitiveSearch = false, conditionMapper,
   } = opts;
 
   let result = originalQuery;
 
   Object.keys(where).forEach((key) => {
-    let query = processFilter(key, castFn, preprocessor);
+    let query = processFilter(key, castFn, preprocessor, conditionMapper);
     const { column, condition } = splitColumnAndCondition(key);
     let queryFn = 'whereRaw';
     if (isAggregateFn) {

tests/knex-flex-filter.test.js

@@ -1,13 +1,13 @@
 
 import seedsFn from './helpers/seeds';
 import knex from './knex';
-import knexFlexFilter, { jsonbPreprocessor } from '../src';
+import knexFlexFilter, { jsonbPreprocessor, defaultPreprocessor, EQ } from '../src';
 
 require('./helpers/database');
 
 
 describe('knex-flex-filter', () => {
-  let castFn;
+  let  castFn;
 
   beforeEach(async (done) => {
     await seedsFn(knex);
@@ -630,4 +630,39 @@ describe('knex-flex-filter', () => {
       done();
     });
   });
+
+  describe('when filtering using the condition mapper', () => {
+    const BLOCK_NUMBER = 5000;
+    it('should correctly use new condition operator @>', async () => {
+      const query = knexFlexFilter(
+        knex.table('entities'),
+        {
+          lastBuyBlockNumber_eq: { lastBuyBlockNumber: BLOCK_NUMBER },
+        },
+        {
+          preprocessor: (column) => {
+            switch (column) {
+              case 'lastBuyBlockNumber':
+                return 'data'; // match against data
+              default:
+                return defaultPreprocessor()(column);
+            }
+          },
+          conditionMapper: (column, condition, defaultValue) => {
+            if (column === 'lastBuyBlockNumber' && condition === EQ) {
+              return '@> ?';
+            }
+            return defaultValue;
+          },
+        },
+      );
+
+      expect(query._statements[0].value.sql).toEqual('data @> ?');
+      expect(query._statements[0].value.bindings).toEqual([{ lastBuyBlockNumber: BLOCK_NUMBER }]);
+
+      const result = await query;
+      
+      expect(parseInt(result[0].data.lastBuyBlockNumber, 10)).toEqual(BLOCK_NUMBER);
+    });
+  });
 });