i have a Json file

js.json

{
 "id": "json",
    "description": "test",
    "packages": [
      {
        "Group": "group1",
        "Name": "name1",
        "Version": "1.0.0"
      },
      {
        "Group": "group2",
        "Name": "name2",
        "Version": "1.0.0"
      },
      {
        "Group": "group3",
        "Name": "name3",
        "Version": "1.0.0"
      },
      {
        "Group": "group5",
        "Name": "name5",
        "Version": "1.0.0"
      }
     ]
    }

It has 4 elements in the .packages array. I want to add a fifth element "group4" to the array to get

 "id": "json",
    "description": "test",
    "packages": [
      {
        "Group": "group1",
        "Name": "name1",
        "Version": "1.0.0"
      },
      {
        "Group": "group2",
        "Name": "name2",
        "Version": "1.0.0"
      },
      {
        "Group": "group3",
        "Name": "name3",
        "Version": "1.0.0"
      },
      {
        "Group": "group4",
        "Name": "name4",
        "Version": "1.0.0"
      },
      {
        "Group": "group5",
        "Name": "name5",
        "Version": "1.0.0"
      }
     ]

if i'm use

jq '.packages[3] |= .   {"Group":"group4", "Name":"name4", "Version":"1.0.0"}' jq.json 

{
 "id": "json",
    "description": "test",
    "packages": [
      {
        "Group": "group1",
        "Name": "name1",
        "Version": "1.0.0"
      },
      {
        "Group": "group2",
        "Name": "name2",
        "Version": "1.0.0"
      },
      {
        "Group": "group3",
        "Name": "name3",
        "Version": "1.0.0"
      },
      {
        "Group": "group4",
        "Name": "name4",
        "Version": "1.0.0"
      }
     ]
    }

And i'm lost group5 element. Is it possible to add an item without losing the previous one? I understand that I can save the output of lost indexes and insert them with the new index, but this seems wrong

CodePudding user response：

Update |= the .packages field by redifining it as a new array consisting of the first three elements .[:3], the new one [{…}] and the the rest .[3:]. Technically, we are constructing an array by piecing three arrays together .

jq '.packages |= .[:3]   [{Group: "group4", Name: "name4", Version: "1.0.0"}]   .[3:]'

{
  "id": "json",
  "description": "test",
  "packages": [
    {
      "Group": "group1",
      "Name": "name1",
      "Version": "1.0.0"
    },
    {
      "Group": "group2",
      "Name": "name2",
      "Version": "1.0.0"
    },
    {
      "Group": "group3",
      "Name": "name3",
      "Version": "1.0.0"
    },
    {
      "Group": "group4",
      "Name": "name4",
      "Version": "1.0.0"
    },
    {
      "Group": "group5",
      "Name": "name5",
      "Version": "1.0.0"
    }
  ]
}

Demo

CodePudding user response：

You want .packages |= . [ { ... } ], which appends an element (well, an entire array, really), to the packages array, and not .packages[3] |= { ... }, which adds/merges some keys into the object at .packages[3].