How to update JSON values in a nested JSON with array in Shell

I have a JSON file payload.json:

{
   "text":"Deployment started :rocket:",
   "blocks":[
      {
         "type":"header",
         "text":{
            "type":"plain_text",
            "text":":computer:  Deployment release  :computer:"
         }
      },
      {
         "type":"context",
         "elements":[
            {
               "type":"mrkdwn",
               "text":"*${{ steps.date.outputs.date }} | STAGING*"
            }
         ]
      },
      {
         "type":"divider"
      },
      {
         "type":"section",
         "text":{
            "type":"mrkdwn",
            "text":"PR_DESCRIPTION"
         }
      },
      {
         "type":"divider"
      },
      {
         "type":"actions",
         "elements":[
            {
               "type":"button",
               "text":{
                  "type":"plain_text",
                  "text":"🚰 Pipeline"
               },
               "url":"${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
            }
         ]
      }
   ],
   "attachments":[
      {
         "color":"warning",
         "fields":[
            {
               "title":"Statut",
               "short":true,
               "value":"Deploying ..."
            }
         ]
      }
   ]
}

And a txt file pr_body.txt:

### TITLE


**bold text**


- qsqds
- qsdqds
- qsdqsd
- qsdqsd

1. qsdqsd
2. qsdqsd
3. qsdqsd
4. qsdqsd

`some code here`

My goal is to replace PR_DESCRIPTION in payload.json with the formatted text in pr_body.txt

Is it possible to do that using jq?

I tried to use jq to update my JSON but due to array object I struggle to find the right way to do it.

I can do it in Python of course but it will be much future proof for me to do it using Shell commands.

Thank you in advance!

>Solution :

You can use the -R option to read in the markdown file as text, and the --argfile option to read in the JSON file. Then, select the nodes with path .blocks[].text.text and content "PR_DESCRIPTION", and set their values to the markdown input, previously stored in a variable:

< pr_body.txt jq -Rs --argfile json payload.json '. as $md | $json
  | (.blocks[].text.text | select(. == "PR_DESCRIPTION")) = $md
'

{
  "text": "Deployment started :rocket:",
  "blocks": [
    {
      "type": "header",
      "text": {
        "type": "plain_text",
        "text": ":computer:  Deployment release  :computer:"
      }
    },
    {
      "type": "context",
      "elements": [
        {
          "type": "mrkdwn",
          "text": "*${{ steps.date.outputs.date }} | STAGING*"
        }
      ]
    },
    {
      "type": "divider"
    },
    {
      "type": "section",
      "text": {
        "type": "mrkdwn",
        "text": "### TITLE\n\n\n**bold text**\n\n\n- qsqds\n- qsdqds\n- qsdqsd\n- qsdqsd\n\n1. qsdqsd\n2. qsdqsd\n3. qsdqsd\n4. qsdqsd\n\n`some code here`\n"
      }
    },
    {
      "type": "divider"
    },
    {
      "type": "actions",
      "elements": [
        {
          "type": "button",
          "text": {
            "type": "plain_text",
            "text": "🚰 Pipeline"
          },
          "url": "${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
        }
      ]
    }
  ],
  "attachments": [
    {
      "color": "warning",
      "fields": [
        {
          "title": "Statut",
          "short": true,
          "value": "Deploying ..."
        }
      ]
    }
  ]
}