Why my string comparison isn't working in bash?

Question

I've a script that does something like this:

set -x

myJson="echo '{\"data\":\"true\"}'"

commandOutput=$(eval $myJson | jq '.data')

echo $commandOutput

while :
do
    if [[ $commandOutput == "true" ]]
    then
        break
    fi
    sleep 1
done

echo "Done"

However, my string comparison never works. The only way I managed this to work was putting '"true"' in the string comparison. It seems that is something related to the eval. Since I've set the x flag here is the output of this script:

+ myJson='echo '\''{"data":"true"}'\'''
++ eval echo ''\''{"data":"true"}'\'''
+++ echo '{"data":"true"}'
++ jq .data
+ commandOutput='"true"'
+ echo '"true"'
"true"
+ :
+ [[ "true" == \t\r\u\e ]]
+ sleep 1
+ :
+ [[ "true" == \t\r\u\e ]]
+ sleep 1
+ :
+ [[ "true" == \t\r\u\e ]]
+ sleep 1

It seems that the string at the right side is being always scaped, if this is the case why is this happening?

Answer 1

As you can see from the trace which you have posted, commandOutput does not hold the string true, but the string "true", so you have to test for this:

 [[ $commandOutput == '"true"' ]]