feat: you can now specify a custom delimiter when distincting on a co…

…lumn (#20)

* feat: you can now specify a custom delimiter when distincting on a column
* chore: update readme

README.md

@@ -230,9 +230,10 @@ select(selection: Array<string> | string)
 
 This function takes an array of values which will be treated as unique.
 Merging the properties from the objects that also have the exact same value of this property.
+The optional concatenation token will default to ', ' but in some cases you want to use a different token, for example when you are working with csv.
 
 ```js
-distinct(properties: Array<string> | string) 
+distinct(properties: Array<string> | string, concatenationToken?: string) 
 ```
 
 **N.B.** this will also sum any numeric fields. If you do not want this behaviour, make that field distinct as well.

package.json

@@ -1,7 +1,7 @@
 {
   "name": "@pennions/joq",
   "private": false,
-  "version": "1.3.0",
+  "version": "1.4.0",
   "type": "module",
   "files": [
     "dist"

src/functions/__tests__/distinct.test.ts

@@ -48,6 +48,16 @@ describe("Tests the distinct function", () => {
         expect(result[0]).toEqual(expected);
     });
 
+    test("It can distinct on a property and merge the other columns with a custom concatenator", () => {
+
+        const expected =  "R01 | R04 | R05 | R06"
+
+        const joq = new JOQ(testArray);
+        joq.distinct("age", " | ");
+        const result = joq.execute();
+        expect(result[0].rollNo).toEqual(expected);
+    });
+
     test("It can distinct on multiple columns", () => {
 
         const expected = {

src/functions/distinct.ts

@@ -1,6 +1,6 @@
 import { getColumnValue } from "./services/value";
 
-export function distinctJsonProperties(jsonArray: Array<any>, columnNames: Array<string>) {
+export function distinctJsonProperties(jsonArray: Array<any>, columnNames: Array<string>, concatenationToken: string) {
 
     /** Nothing to distinct */
     if (!columnNames || !columnNames.length) {
@@ -87,7 +87,7 @@ export function distinctJsonProperties(jsonArray: Array<any>, columnNames: Array
     mergedObjects.forEach((jsonObject: any) => {
         for (const prop in jsonObject) {
             if (Array.isArray(jsonObject[prop])) {
-                jsonObject[prop] = jsonObject[prop].join(", ");
+                jsonObject[prop] = jsonObject[prop].join(concatenationToken);
             }
         }
     });

src/joq.ts

@@ -13,6 +13,7 @@ class JOQ {
     private selection: Array<string> = [];
     private groupByProperties: Array<string> = [];
     private distinctProperties: Array<string> = [];
+    private concatenationToken: string = ', ';
 
     /**
      * Jelmers Object Query Class
@@ -114,7 +115,12 @@ class JOQ {
     /** 
      * distinct on specified columns in objects and make them unique and merge the other properties
      */
-    distinct(properties: Array<string> | string) {
+    distinct(properties: Array<string> | string, concatenationToken?: string) {
+
+        if (concatenationToken) {
+            this.concatenationToken = concatenationToken;
+        }
+
         if (Array.isArray(properties)) {
             this.distinctProperties = properties;
         }
@@ -130,7 +136,7 @@ class JOQ {
         const copyOfModel = JSON.parse(JSON.stringify(this.model));
         const filteredJsonArray = filterJsonArray(copyOfModel, this.filterDetails);
         const sortedJsonArray = sortJsonArray(filteredJsonArray, this.sortDetails);
-        const distinctJsonArray = distinctJsonProperties(sortedJsonArray, this.distinctProperties);
+        const distinctJsonArray = distinctJsonProperties(sortedJsonArray, this.distinctProperties, this.concatenationToken);
         const selectedJsonArray = selectJsonArray(distinctJsonArray, this.selection);
         const groupedJsonArray = groupJsonArray(selectedJsonArray, this.groupByProperties);
         return groupedJsonArray;