jq-shvars.sh

#!/usr/bin/env bash

set -o errexit -o nounset

IFS=$'\n' read -r -d '' < <(
  while [[ $# -gt 0 ]]
  do
    if [[ "$1" =~ ^([a-zA-Z0-9_]+)=(.+)$ ]]
    then printf -- 'declare -- %s=\(%s|tostring);' "${BASH_REMATCH[1]}" "${BASH_REMATCH[2]}"
    fi
    shift
  done
) || true

jq --raw-output "@sh \"${REPLY}\""

Usage:

IFS=$'\n' read -r -d '' <<'EOF' || true
{
  "name": "Matt",
  "emails": [
    "matt.helm@mehnet.io"
  ]
}
EOF

eval "$(./jq-shvars.sh USER_NAME='.name' USER_EMAIL='.emails[0]' <<<"$REPLY")"

declare -p USER_NAME USER_EMAIL
#declare -- USER_NAME="Matt"
#declare -- USER_EMAIL="matt.helm@mehnet.io"

This little utility makes it easy to parse out JSON values into shell variables.