Merge pull request #9 from Terminal-Systems/feature/operator-mapper

Add ability to specify custom conditionMapper

Author: dmerrill6

README.md

@@ -165,6 +165,29 @@ const query = knexFlexFilter(
 
 Set to `true` if you want to use insensitive-case searches when using `contains` or `starts_with` filters. Defaults to false.
 
+### conditionMapper
+Useful to transform/change the default operator or condition that a 
+particular filter is being evaluated against. `conditionMapper` receives the column name, the condition being evaluated and the default/normal value that should returned for the condition.
+
+For example, here we change the `contains` condition to use json containment operator `@>`:
+
+```javascript
+import { knexFlexFilter, CONTAINS } from 'knex-flex-filter';
+...
+
+const opts = {
+  conditionMapper: (column, condition, defaultValue) => {
+    if (condition === CONTAINS) {
+      return '@> ?';
+    }
+
+    return defaultValue;
+  }
+}
+
+knexFlexFilter(baseQuery, where, opts).then(console.log);
+```
+
 ## Contributing
 
 Make sure all the tests pass before sending a PR. To run the test suite, run `yarn test`. Please note that the codebase is using `dotenv` package to connect to a test db, so, to connect to your own, add a `.env` file inside the `tests` folder with the following structure:

src/index.js

@@ -72,6 +72,18 @@ export const dbTypes = [
 
 const sanitize = identifier => identifier.replace(/([^A-Za-z0-9_]+)/g, '');
 
+const getCondition = (conditionMapper, column, condition) => {
+  let currCondition = conditionMap[condition];
+  if (conditionMapper) {
+    const mappedCondition = conditionMapper(column, condition, currCondition);
+    if (mappedCondition) {
+      currCondition = mappedCondition;
+    }
+  }
+
+  return currCondition;
+};
+
 export const defaultPreprocessor = () => filterKey => `"${sanitize(filterKey)}"`;
 
 export const jsonbPreprocessor = jsonbColumn => filterKey => `${sanitize(jsonbColumn)}->>'${sanitize(filterKey)}'`;
@@ -90,7 +102,7 @@ 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 +117,7 @@ const processFilter = (filterQS, castFn, preprocessor) => {
     if (cast) query = `(${preprocessed})::${cast}`;
   }
 
-  const currCondition = conditionMap[condition];
+  let currCondition = getCondition(conditionMapper, column, condition);
   if (currCondition.includes('??')) {
     return currCondition.replace('??', query);
   }
@@ -116,13 +128,13 @@ 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) {
@@ -133,7 +145,7 @@ export const knexFlexFilter = (originalQuery, where = {}, opts = {}) => {
     let value = where[key];
 
     // Escape apostrophes correctly
-    const matchEscape = conditionMap[condition].match(/'(.*)\?(.*)'/);
+    const matchEscape = getCondition(conditionMapper, column, condition).match(/'(.*)\?(.*)'/);
     if (matchEscape) {
       // eslint-disable-next-line no-unused-vars
       const [_, pre, post] = matchEscape;

tests/knex-flex-filter.test.js

@@ -1,7 +1,7 @@
 
 import seedsFn from './helpers/seeds';
 import knex from './knex';
-import knexFlexFilter, { jsonbPreprocessor } from '../src';
+import knexFlexFilter, { jsonbPreprocessor, defaultPreprocessor, EQ } from '../src';
 
 require('./helpers/database');
 
@@ -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);
+    });
+  });
 });