Learning JSON Schema

This is the basic learning for JSON schema.
It is used for creating JSON easier like having an intellisense with guide and validations.

Getting Started

1. Open vscode
2. Create schemas folder
3. Create your-filename.schema.json and open it
4. Tell vscode about your JSON schemas. Go here
5. Write { }
6. Press Ctrl + SPACE and input or select "$schema"
7. Press again Ctrl + SPACE and choose a specification (i.e. http://json-schema.org/schema)

You can now define your own schema! See examples below...

Examples

schemas/profile.schema.json

{
    "$schema": "http://json-schema.org/schema",
    "$id": "profile.schema.json",
    "required": ["name", "age"],
    "properties": {
        "name": {
            "description": "Give details about your name.",
            "$ref": "./name.schema.json"
        },
        "hobbies": {
            "description": "Things you love to do on your free or \"me\" time.",
            "$ref": "#/definitions/hobbiesdef"
        },
        "age": {
            "description": "How old are you?",
            "$ref": "#/definitions/agedef"
        }
    },
    "definitions": {
        "hobbiesdef": {
            "$comment": "definitions are sub-schemas, and called in $ref, you can also create another schema file rather than having a definition",
            "type": "array",
            "uniqueItems": true,
            "items": {
                "type": "string",
                "examples": [
                    "swimming",
                    "sleeping",
                    "eating",
                    "watching movies",
                    "playing music instruments",
                    "listening to music",
                    "playing outdoor games",
                    "playing video games",
                    "games"
                ]
            },
            "examples": [
                ["swimming", "doing laundry"],
                ["playing games", "while eating"]
            ]
        },
        "agedef": {
            "type": "integer",
            "exclusiveMinimum": 0
        }
    }
}

schemas/name.schema.json

{
    "$schema": "http://json-schema.org/schema",
    "$id": "name.schema.json",
    "required": ["firstName", "lastName"],
    "additionalProperties": false,
    "properties": {
        "firstName": {
            "description": "Your first name goes here.",
            "type": "string"
        },
        "lastName": {
            "description": "Your surname goes here.",
            "type": "string"
        },
        "nickname": {
            "description": "Enter here what you want your close friends to call you.",
            "type": "string"
        },
        "prefix": {
            "description": "How you are addressed.",
            "type": "string",
            "enum": ["Mr.", "Ms.", "Dr.", "Sir", "Madam"]
        },
        "suffix": {
            "description": "Your suffix (if any).",
            "type": "string",
            "examples": ["Jr", "Sr"]
        }
    }
}

Sample Model

profile.model.json

{
    "name": {
        "firstName": "Juan",
        "lastName": "De La Cruz",
        "suffix": "III"
    },
    "hobbies": [
        "playing games",
        "while eating",
        "listening to music",
        "listening to IU music"
    ],
    "age": 3
}

Settings

You need to setup and tell vscode about your schema and where to apply it.
So that the intellisense, validation will display every time you write your JSON object/model.

1. Press Ctrl + P
2. Type >settings
3. Select Preferences: Open Workspace Settings (JSON)
4. Validate that the following is created: .vscode/settings.json
5. You can now use its intellisense to construct the following:
   

.vscode/settings.json

{
    "json.schemas": [
        {
            "fileMatch": ["*profile.model.json"],
            "url": "./schemas/profile.schema.json"
        }
    ]
}

References

• https://json-schema.org/learn/getting-started-step-by-step

Extra tools

• Quicktype: https://github.com/quicktype/quicktype

  This tool can create a schema out from a plain JSON
  Also, it can create a Typescript Interface straight from the schema!

npm install -g quicktype

Generating code from JSON schema

The recommended way to use quicktype is to generate a JSON schema from sample data, review and edit the schema, commit the schema to your project repo, then generate code from the schema as part of your build process:

# First, infer a JSON schema from a sample.
quicktype pokedex.json -l schema -o schema.json

# Review the schema, make changes,
# and commit it to your project repo.

# Finally, generate model code from schema in your
# build process for whatever languages you need:
quicktype -s schema schema.json -o src/ios/models.swift
quicktype -s schema schema.json -o src/android/Models.java
quicktype -s schema schema.json -o src/nodejs/Models.ts

# All of these models will serialize to and from the same
# JSON, so different programs in your stack can communicate
# seamlessly.