awesome-ajv-errors

awesome-ajv-errors pretty-prints ajv errors

It has a gorgeous human-understandable output, predicts human errors and suggests fixes.

Contents

• Examples
• Usage

Versions

• Since version 2;
  • This is a pure ESM package. It requires Node 12.20 and cannot be used from CommonJS.
  • Ajv 6, 7 and 8 are supported.
• Since version 3;
  • This package can be used in browsers without special hacks. It will by default not pretty-print codeframes or use colors. If you want this, you have two options:
    • Either import from awesome-ajv-errors/node explicitly (if you have e.g. webpack DefinePlugin configured to hack around missing things like process is not defined), or
    • Import from awesome-ajv-errors/try-styled which has a promise-based prettify function (prettifyTryStyled) or a promise which will eventually resolve to a synchronous function (styledPrettify).
    • Both of these will fallback to non-colored non-codeframe output if e.g. loading @babel/code-frame failed. This will likely be entirely resolved once Babel 8 is released; then awesome output will by default work in browsers too.

Examples

Similar property name

Suggest similar properties

JSON Schema and data

schema.json

{
  "title": "Second-level two similar properties",
  "type": "object",
  "properties": {
    "foo": {
      "type": "object",
      "properties": {
        "bar": {},
        "bak": {}
      },
      "additionalProperties": false
    }
  }
}

data.json

{
  "foo": {
    "bar": "42",
    "baz": "33"
  }
}

Multiple similar property names

Suggests multiple valid property names

JSON Schema and data

schema.json

{
  "title": "Second-level three similar properties",
  "type": "object",
  "properties": {
    "foo": {
      "type": "object",
      "properties": {
        "bar": {},
        "bak": {},
        "bam": {}
      },
      "additionalProperties": false
    }
  }
}

data.json

{
  "foo": {
    "bar": "42",
    "baz": "33"
  }
}

Type typo

Suggests the valid value type when mistaken

JSON Schema and data

schema.json

{
  "title": "One option (number to string)",
  "type": "object",
  "properties": {
    "foo": {
      "anyOf": [
        {
          "type": "string"
        }
      ]
    }
  }
}

data.json

{
  "foo": 42
}

Type typo (reverse)

Suggests the valid value type when mistaken

JSON Schema and data

schema.json

{
  "title": "One option (string to number)",
  "type": "object",
  "properties": {
    "foo": {
      "anyOf": [
        {
          "type": "number"
        }
      ]
    }
  }
}

data.json

{
  "foo": "42"
}

Type typo (one much better option)

When the type mismatch, and one type is much "better" than the rest (as in probably the right solution), it will be suggested for conversion

JSON Schema and data

schema.json

{
  "title": "Two options",
  "type": "object",
  "properties": {
    "foo": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "boolean"
        }
      ]
    }
  }
}

data.json

{
  "foo": 42
}

Type typo (one much better option out of multiple)

JSON Schema and data

schema.json

{
  "title": "Three options",
  "type": "object",
  "properties": {
    "foo": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "boolean"
        },
        {
          "type": "null"
        }
      ]
    }
  }
}

data.json

{
  "foo": 42
}

Array too small

JSON Schema and data

schema.json

{
  "title": "2 too few",
  "type": "object",
  "properties": {
    "foo": {
      "type": "array",
      "minItems": 3
    }
  }
}

data.json

{
  "foo": [
    1
  ]
}

Number too big

JSON Schema and data

schema.json

{
  "title": "Less than or equal to",
  "type": "object",
  "properties": {
    "foo": {
      "type": "number",
      "maximum": 17
    }
  }
}

data.json

{
  "foo": 42
}

Not in enum set

JSON Schema and data

schema.json

{
  "title": "One value of same type",
  "type": "object",
  "properties": {
    "foo": {
      "enum": [
        41
      ]
    }
  }
}

data.json

{
  "foo": 42
}

Almost in enum set (wrong convertible type)

JSON Schema and data

schema.json

{
  "title": "Two options (one of different type)",
  "type": "object",
  "properties": {
    "foo": {
      "enum": [
        41,
        "42"
      ]
    }
  }
}

data.json

{
  "foo": 42
}

Almost in enum set (wrong convertible type), multiple options

JSON Schema and data

schema.json

{
  "title": "Four options (one of different type)",
  "type": "object",
  "properties": {
    "foo": {
      "enum": [
        "falso",
        "other",
        "False",
        false
      ]
    }
  }
}

data.json

{
  "foo": "false"
}

Invalid format (time)

JSON Schema and data

schema.json

{
  "title": "time invalid",
  "type": "object",
  "properties": {
    "foo": {
      "type": "string",
      "format": "time"
    }
  }
}

data.json

{
  "foo": "11:22:334"
}

Invalid format (e-mail)

JSON Schema and data

schema.json

{
  "title": "email invalid",
  "type": "object",
  "properties": {
    "foo": {
      "type": "string",
      "format": "email"
    }
  }
}

data.json

{
  "foo": "quite@[e-mail]"
}

if-then not satisfied

JSON Schema and data

schema.json

{
  "title": "if-then on first-level object",
  "properties": {
    "foo": {
      "if": {
        "properties": {
          "firstName": {
            "const": true
          }
        }
      },
      "then": {
        "required": [
          "lastName"
        ]
      }
    }
  }
}

data.json

{
  "foo": {
    "firstName": true
  }
}

Multiple of

JSON Schema and data

schema.json

{
  "title": "Multiple of",
  "type": "object",
  "properties": {
    "foo": {
      "type": "number",
      "multipleOf": 4
    }
  }
}

data.json

{
  "foo": 17
}

Required property

JSON Schema and data

schema.json

{
  "title": "Root-level required",
  "type": "object",
  "properties": {
    "foo": {}
  },
  "required": [
    "foo"
  ]
}

data.json

{
  "bar": 42
}

Usage

Import the ajv package, and prettify from awesome-ajv-errors:

import * as Ajv from 'ajv'
import { prettify } from 'awesome-ajv-errors'

Create an ajv instance and validate objects:

const ajv = new Ajv( { allErrors: true } ); // allErrors is optional

let data, schema; // Get the JSON schema and the JSON data from somewhere

const validate = ajv.compile( schema );
validate( data );

Now, the validation error is stored on the validate function. Use prettify to pretty-print the errors, and provide the data so that awesome-ajv-errors can suggest fixes:

console.log( prettify( validate, { data } ) );