Dynamodb Marshall by JQ

modules.jq

def marshall:
  def m:
    def to_string: {S:.};
    def to_number: {N:.|tostring};
    def to_boolean: {BOOL:.};
    def to_array: {L:.|to_entries|map(.value|m)};
    def to_object: {M:.|map_values(m)};
    def to_null: {NULL:true};
    if .|type=="string" then .|to_string
    elif .|type=="number" then .|to_number
    elif .|type=="boolean" then .|to_boolean
    elif .|type=="array" then .|to_array
    elif .|type=="object" then .|to_object
    elif .|type=="null" then .|to_null
    else . end;
  .|map_values(m);

➜ jq 'include "modules"; . | marshall' <<< '{"name":"Jane","age":42, "colors": ["red", "green"],"items":{"a": 1}}'
{
  "name": {
    "S": "Jane"
  },
  "age": {
    "N": "42"
  },
  "colors": {
    "L": [
      {
        "S": "red"
      },
      {
        "S": "green"
      }
    ]
  },
  "items": {
    "M": {
      "a": {
        "N": "1"
      }
    }
  }
}