JSON Semantic Diff

Spruce is a general purpose YAML & JSON merging tool, and one of it's subcommands is a semantic JSON diff. It captures added and removed fields, and highlights any type changes.

Installing Spruce

Spruce is written in Go, and can be installed in many different ways:

1. With mise (which I highly recommend):

   bash
   mise use -g github:geofffranks/spruce

2. With brew if you're on MacOS

   bash
   brew install starkandwayne/cf/spruce

3. With go get:

   bash
   go get github.com/geofffranks/spruce

Example usage

Here are two sample JSON files. Between the first and the second, I've changed a value, changed two data types, and removed two fields:

json
{
  "name": "Alice",
  "age": "30",
  "pets": "Fido",
  "favourite_cake": "Carrot cake",
  "another": {
    "value": "here"
  }
}

json
{
  "name": "Alice Smith",
  "age": 30,
  "pets": ["Fido"],
  "another": {}
}

If we run spruce diff, this information is returned to us in a format that makes is very easy to see the diffs:

diff
$ spruce diff first.json second.json
(root level)
- one map entry removed:
favourite_cake: "Carrot cake"
age
± type change from string to int
- 30
+ 30
another
- one map entry removed:
value: here
name
± value change
- Alice
+ Alice Smith
pets
± type change from string to list
- Fido
+ - Fido