How to change json object using jq bash - linux

Question

I have a json object that looks like below:
{
"CallerReference": "terraform-20210518124856158900000001",
"Aliases": {
"Quantity": 3,
"Items": [
"consumer-portal.mlb.effi.com.au",
"*.mlb.effi.com.au",
"coolvalue.mylocalbroker.com.au"
]
}
}
And I need to;
First get the value of Quantity
Increment it by 1
Then change that value so it looks like "Quantity": 4,
And I need to add another entry at the bottom of the Items array.
I am using jq and trying to first replace the "Quantity" value as below:
filename=cf.json
rm $filename
aws cloudfront get-distribution-config --id <ID> \
--query 'DistributionConfig' --output json > $filename
etag=$(aws cloudfront get-distribution-config --id <ID> |
jq -r '.ETag')
aws cloudfront update-distribution \
--distribution-config file://$filename --id <ID> --if-match $etag > /dev/null
jq --argjson i "10" '.Aliases.Quantity[$i]' $filename
But I am getting this error:
jq: error (at cf.json:136): Cannot index number with number

Answer 1

Sounds like += should to the trick [docs]
.Aliases.Quantity += 1 To increment Quantity by 1
.Aliases.Items += [ "Example" ] To add a new index to the Items array
Full command:
jq '.Aliases.Quantity += 1 | .Aliases.Items += [ "Example" ]'
Online demo
{
"CallerReference": "terraform-20210518124856158900000001",
"Aliases": {
"Quantity": 4,
"Items": [
"consumer-portal.mlb.effi.com.au",
"*.mlb.effi.com.au",
"coolvalue.mylocalbroker.com.au",
"Example"
]
}
}