# Generate JSON format based on payload array

**URL:** <https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907>\
**Category:** General\
**Created:** [24 June 2024 13:14 UTC](https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907 "2024-06-24T13:14:06Z")\
**Posts on this page:** 9\
**Page:** 1

<div class="post-metadata">

**Author:** ![grawsom](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/grawsom/32/53070_2.png) [@grawsom](https://discourse.nodered.org/u/grawsom)\
**Post date:** [24 June 2024 13:14 UTC](https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907/1 "2024-06-24T13:14:06Z")

</div>

This is over my head.  
I want to format a JSON output based on a array input, but only where some of the parameters is build.

If I have this ex. array `["CAR1","CAR2"]`  
It will give me this output

```auto
    "id": "TEST",
    "time": "2024-06-24 13:56:36",
    "vehicles": [
        {
            "id": "CAR1",
            "car_time": "2024-06-24 13:56:36",
            "test": [
                {
                    "test_code": "40000",
                    "test_time": "2024-06-24 13:56:36"
                }
            ]
        },
        {
            "id": "CAR2",
            "car_time": "2024-06-24 13:56:36",
            "test": [
                {
                    "test_code": "40000",
                    "test_time": "2024-06-24 13:56:36"
                }
            ]
        }
    ]
}

```

The vehicles part needs to be looped, based on the array, where only the the "id" part will be filled with info from the array.

Hope this makes sence

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [24 June 2024 13:34 UTC](https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907/2 "2024-06-24T13:34:20Z")

</div>

Here is a "no-code" method:

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/e/e/ee9bcfc77716f5f1d2654e9c5e15d0127439555a.png)

```auto
[{"id":"350b2ac7fd8d0c02","type":"inject","z":"484e8001f595ac21","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":1370,"y":100,"wires":[["d13e74230b22ea79"]]},{"id":"d13e74230b22ea79","type":"template","z":"484e8001f595ac21","name":"template","field":"template","fieldType":"msg","format":"handlebars","syntax":"mustache","template":"{\n \"id\": \"\",\n \"car_time\": \"2024-06-24 13:56:36\",\n \"test\": [\n {\n \"test_code\": \"40000\",\n \"test_time\": \"2024-06-24 13:56:36\"\n }\n]\n}","output":"json","x":1530,"y":100,"wires":[["a36c01bcbdac4f42"]]},{"id":"a36c01bcbdac4f42","type":"change","z":"484e8001f595ac21","name":"populate car array","rules":[{"t":"set","p":"payload","pt":"msg","to":"[\"CAR1\", \"CAR2\", \"CAR3\"]","tot":"json"}],"action":"","property":"","from":"","to":"","reg":false,"x":1710,"y":100,"wires":[["4f6ee2101845991c"]]},{"id":"4f6ee2101845991c","type":"split","z":"484e8001f595ac21","name":"","splt":"\\n","spltType":"str","arraySplt":1,"arraySpltType":"len","stream":false,"addname":"","property":"payload","x":1370,"y":180,"wires":[["31d79af157a7d2ef"]]},{"id":"31d79af157a7d2ef","type":"change","z":"484e8001f595ac21","name":"apply template","rules":[{"t":"set","p":"car","pt":"msg","to":"payload","tot":"msg"},{"t":"set","p":"payload","pt":"msg","to":"template","tot":"msg","dc":true},{"t":"set","p":"payload.id","pt":"msg","to":"car","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":1560,"y":180,"wires":[["14bb75521a04bd36"]]},{"id":"14bb75521a04bd36","type":"join","z":"484e8001f595ac21","name":"","mode":"auto","build":"object","property":"payload","propertyType":"msg","key":"topic","joiner":"\\n","joinerType":"str","accumulate":true,"timeout":"","count":"","reduceRight":false,"reduceExp":"","reduceInit":"","reduceInitType":"","reduceFixup":"","x":1740,"y":180,"wires":[["c0e88d03d870b545"]]},{"id":"7229b6af4a0552b4","type":"debug","z":"484e8001f595ac21","name":"debug 429","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":1720,"y":260,"wires":[]},{"id":"c0e88d03d870b545","type":"change","z":"484e8001f595ac21","name":"finalise output","rules":[{"t":"set","p":"temp","pt":"msg","to":"payload","tot":"msg"},{"t":"set","p":"payload","pt":"msg","to":"{\"id\":\"TEST\",\"time\":\"2024-06-24 13:56:36\",\"vehicles\":[]}","tot":"json"},{"t":"set","p":"payload.time","pt":"msg","to":"","tot":"date"},{"t":"move","p":"temp","pt":"msg","to":"payload.vehicles","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":1420,"y":260,"wires":[["7229b6af4a0552b4"]]}]

```

It may require some tweaks but hopefully you get enough clues to move forward

---

<div class="post-metadata">

**Author:** ![grawsom](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/grawsom/32/53070_2.png) [@grawsom](https://discourse.nodered.org/u/grawsom)\
**Post date:** [24 June 2024 13:35 UTC](https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907/3 "2024-06-24T13:35:46Z")

</div>

I will take a look at that - thanks

---

<div class="post-metadata">

**Author:** ![E1cid](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/e1cid/32/77971_2.png) [@E1cid](https://discourse.nodered.org/u/E1cid)\
**Post date:** [24 June 2024 15:26 UTC](https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907/4 "2024-06-24T15:26:20Z")

</div>

Here is another low code way

```auto
[{"id":"350b2ac7fd8d0c02","type":"inject","z":"d1395164b4eec73e","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":100,"y":4720,"wires":[["a36c01bcbdac4f42"]]},{"id":"a36c01bcbdac4f42","type":"change","z":"d1395164b4eec73e","name":"populate car array","rules":[{"t":"set","p":"payload","pt":"msg","to":"[\"CAR1\", \"CAR2\", \"CAR3\"]","tot":"json"},{"t":"set","p":"timestamp","pt":"msg","to":"2024-06-24 13:56:36","tot":"str"}],"action":"","property":"","from":"","to":"","reg":false,"x":270,"y":4720,"wires":[["d13e74230b22ea79"]]},{"id":"d13e74230b22ea79","type":"template","z":"d1395164b4eec73e","name":"template","field":"payload","fieldType":"msg","format":"handlebars","syntax":"mustache","template":"{\n \"id\":\"TEST\",\n \"time\":\"{{timestamp}}\",\n \"vehicles\":[\n {}\n {{#payload}},{\n \"id\":\"{{.}}\",\n \"car_time\": \"{{timestamp}}\",\n \"test\":[\n {\n \"test_code\":\"40000\",\n \"test_time\":\"{{timestamp}}\"\n }\n]\n }{{/payload}}\n ]\n}","output":"json","x":440,"y":4720,"wires":[["4b06ef952d71c9a4"]]},{"id":"4b06ef952d71c9a4","type":"change","z":"d1395164b4eec73e","name":"","rules":[{"t":"delete","p":"payload.vehicles[0]","pt":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":650,"y":4720,"wires":[["7229b6af4a0552b4"]]},{"id":"7229b6af4a0552b4","type":"debug","z":"d1395164b4eec73e","name":"debug 429","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":450,"y":4780,"wires":[]}]

```

 ![chrome_screenshot_24 Jun 2024 16_24_59 BST](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/e/e/ee854a2260392979648091f441cda7acc376c891.png)

More info on mustache here [mustache(5) - Logic-less templates.](https://mustache.github.io/mustache.5.html)

---

<div class="post-metadata">

**Author:** ![grawsom](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/grawsom/32/53070_2.png) [@grawsom](https://discourse.nodered.org/u/grawsom)\
**Post date:** [25 June 2024 10:11 UTC](https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907/5 "2024-06-25T10:11:02Z")

</div>

I like both suggestions, but the last one fits my needs the best.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [9 July 2024 10:11 UTC](https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907/6 "2024-07-09T10:11:13Z")

</div>

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.

---

<div class="post-metadata">

**Author:** ![E1cid](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/e1cid/32/77971_2.png) [@E1cid](https://discourse.nodered.org/u/E1cid)\
**Post date:** [17 March 2025 12:47 UTC](https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907/7 "2025-03-17T12:47:29Z")

</div>



---

<div class="post-metadata">

**Author:** ![grawsom](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/grawsom/32/53070_2.png) [@grawsom](https://discourse.nodered.org/u/grawsom)\
**Post date:** [17 March 2025 14:00 UTC](https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907/8 "2025-03-17T14:00:05Z")

</div>

In my example - if you want to have more than 1 value that gets replaced.

If I have this ex. array `["CAR1","CAR2"]`, and a second array `["CODE1","CODE2"]`  
It will give me this output

```auto
"id": "TEST",
    "time": "2024-06-24 13:56:36",
    "vehicles": [
        {
            "id": "CAR1",
            "car_time": "2024-06-24 13:56:36",
            "test": [
                {
                    "test_code": "CODE1",
                    "test_time": "2024-06-24 13:56:36"
                }
            ]
        },
        {
            "id": "CAR2",
            "car_time": "2024-06-24 13:56:36",
            "test": [
                {
                    "test_code": "CODE2",
                    "test_time": "2024-06-24 13:56:36"
                }
            ]
        }
    ]
}

```

The vehicles part needs to be looped, based on the array, where "id" and "test\_code" part will be filled with info from the arrays.

I can get one value to be build, but can't figure out with 2 value (arrays)

---

<div class="post-metadata">

**Author:** ![E1cid](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/e1cid/32/77971_2.png) [@E1cid](https://discourse.nodered.org/u/E1cid)\
**Post date:** [17 March 2025 14:56 UTC](https://discourse.nodered.org/t/generate-json-format-based-on-payload-array/88907/9 "2025-03-17T14:56:11Z")

</div>

All the data would need to be in the single array. Otherwise you would have to move to a function node and Javascript, or a change node and use JSONata

```auto
[
    {
        "car": "CAR1",
        "code": "code1"
    },
    {
        "car": "CAR2",
        "code": "code2"
    },
    {
        "car": "CAR3",
        "code": "code3"
    }
]

```

then the mustache would be

```auto
{
    "id":"TEST",
    "time":"{{timestamp}}",
    "vehicles":[
        {}
        {{#payload}},{
            "id":"{{car}}",
            "car_time": "{{timestamp}}",
            "test":[
                {
                    "test_code":"{{code}}",
                    "test_time":"{{timestamp}}"
                }
            ]
        }{{/payload}}
    ]
}

```

Example flow

```auto
[{"id":"59754b0558eb72a8","type":"inject","z":"d1395164b4eec73e","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":300,"y":5720,"wires":[["ea99fa2b1097c829"]]},{"id":"ea99fa2b1097c829","type":"change","z":"d1395164b4eec73e","name":"populate car array","rules":[{"t":"set","p":"payload","pt":"msg","to":"[{\"car\":\"CAR1\",\"code\":\"code1\"},{\"car\":\"CAR2\",\"code\":\"code2\"},{\"car\":\"CAR3\",\"code\":\"code3\"}]","tot":"json"},{"t":"set","p":"timestamp","pt":"msg","to":"2024-06-24 13:56:36","tot":"str"}],"action":"","property":"","from":"","to":"","reg":false,"x":470,"y":5720,"wires":[["b2cc68a35508d8df"]]},{"id":"b2cc68a35508d8df","type":"template","z":"d1395164b4eec73e","name":"template","field":"payload","fieldType":"msg","format":"handlebars","syntax":"mustache","template":"{\n \"id\":\"TEST\",\n \"time\":\"{{timestamp}}\",\n \"vehicles\":[\n {}\n {{#payload}},{\n \"id\":\"{{car}}\",\n \"car_time\": \"{{timestamp}}\",\n \"test\":[\n {\n \"test_code\":\"{{code}}\",\n \"test_time\":\"{{timestamp}}\"\n }\n]\n }{{/payload}}\n ]\n}\n","output":"json","x":640,"y":5720,"wires":[["3032d31027ee9184"]]},{"id":"3032d31027ee9184","type":"change","z":"d1395164b4eec73e","name":"","rules":[{"t":"delete","p":"payload.vehicles[0]","pt":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":850,"y":5720,"wires":[["d113f78eafbb3a8e"]]},{"id":"d113f78eafbb3a8e","type":"debug","z":"d1395164b4eec73e","name":"debug 429","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":650,"y":5780,"wires":[]}]

```