---
title: Using reduce() to construct a JSON.
description: Learn how to send multiple points with http.post() by creating a JSON object with reduce().
url: https://docs.influxdata.com/resources/how-to-guides/reduce-to-construct-json/
estimated_tokens: 2877
---

# Using reduce() to construct a JSON.

## Send data in JSON body with `http.post()`

Use the [reduce()](/flux/v0/stdlib/universe/reduce/) function to create a JSON object to include as the body with `http.post()`.

1. Import both the [array](/flux/v0/stdlib/array/) package to query data and construct table(s), and the [http package](/flux/v0/stdlib/http/) to transfer JSON over http.
    
2. Use `array.from()` to query data and construct a table. Or, use another method [to query data with Flux](/influxdb/v2/query-data/flux/).
    
3. Use the `reduce()` function to construct a JSON object, and then use `yield()` to store the output of reduce. This table looks like:
    
    | field | tag |
    | --- | --- |
    | example-field:[“3"4"1 | {example-tag-key:[“bar"bar"bar |
    
4. Use the [map()](/flux/v0/stdlib/universe/map/) function to combine the two components together into a JSON object, and then use a second `yield()` function to store this object as `final JSON`. This table looks like:
    
    | field | tag | final |
    | --- | --- | --- |
    | example-field:[“3"4"1 | {example-tag-key:[“bar"bar"bar | {example-tag-key:[“bar"bar"bar] , example-field:[“3"4"1]} |
    
5. Use the `findRecord()` function to extract the value from the final column, the JSON.
    
6. Use `http.post()` to specify a URL to sent the JSON to. In this example, we use [Post Test Server](https://ptsv2.com/) as URL to send the JSON to, and test the `http.post()` function.
    

```js
import "array"
import "http"

 
data = array.from(
        rows: [
            {_time: 2020-01-01T00:00:00Z, _field: "example-field", _value: 3, foo: "bar"},
            {_time: 2020-01-01T00:01:00Z, _field: "example-field", _value: 4, foo: "bar"},
            {_time: 2020-01-01T00:02:00Z, _field: "example-field", _value: 1, foo: "bar"},
        ],
    )
  
    |> reduce(
            fn: (r, accumulator) => ({tag:accumulator.tag + "\"" + r.foo, 
                                    field : accumulator.field + "\"" + string(v:r._value)
                                    }),
            identity: {tag: "{example-tag-key:[", 
                    field: "example-field:[" }
    )
    |> yield(name: "output of reduce")
    |> map(fn: (r) => ({ r with tag: r.tag + "]" }))
    |> map(fn: (r) => ({ r with field: r.field + "]}" }))
    |> map(fn: (r) => ({ r with final: r.tag + " , " + r.field}))
    |> yield(name: "final JSON")
    |> findRecord(
        fn: (key) => true,
        idx: 0,
        )

http.post(
    url: "https://ptsv2.com/t/c4x38-1656014222/post",
    headers: {"Content-type": "application/json"},
    data: bytes(v: data.final),
    )
```