The ajv-cli package is a command-line interface for the Ajv JSON schema validator. It allows users to validate JSON data against JSON schemas, compile schemas, and perform other schema-related tasks directly from the command line.
Validate JSON data against a schema
This command validates JSON data in 'data.json' against the JSON schema in 'schema.json'. If the data is valid, the command will exit with a status code of 0; otherwise, it will print validation errors.
ajv validate -s schema.json -d data.jsonCompile a JSON schema
This command compiles the JSON schema in 'schema.json' and outputs the compiled schema to 'compiledSchema.js'. The compiled schema can be used for faster validation in JavaScript applications.
ajv compile -s schema.json -o compiledSchema.jsGenerate a schema from JSON data
This command generates a JSON schema based on the structure of the JSON data in 'data.json' and outputs the schema to 'schema.json'. This is useful for creating initial schemas from example data.
ajv generate -d data.json -o schema.jsonThe jsonschema package is a library for validating JSON objects against JSON schemas. It provides a programmatic API for validation but does not include a command-line interface like ajv-cli.
Joi is a powerful schema description language and data validator for JavaScript objects. It is more focused on JavaScript object validation and does not natively support JSON schema validation or a command-line interface.
z-schema is a JSON schema validator that supports the latest JSON schema draft specifications. It provides a programmatic API for validation but does not include a command-line interface like ajv-cli.
Command line interface for ajv, one of the fastest json schema validators. Supports JSON, JSON5, and YAML.
npm install -g ajv-cli
Parameter --spec can be used with all commands (other than help) to choose JSON schema language:
--spec=draft7 (default) - support JSON Schema draft-07 (uses import Ajv from "ajv")--spec=draft2019 - support JSON Schema draft-2019-09 (uses import Ajv from "ajv/dist/2019")--spec=draft2020 - support JSON Schema draft-2020-12 (uses import Ajv from "ajv/dist/2020")--spec=jtd - support JSON Type Definition (uses import Ajv from "ajv/dist/jtd")ajv help
ajv help validate
ajv help compile
ajv help migrate
ajv help test
This command validates data files against JSON-schema
ajv validate -s test/schema.json -d test/valid_data.json
ajv -s test/schema.json -d test/valid_data.json
You can omit validate command name and .json from the input file names.
-s - file name of JSON-schemaOnly one schema can be passed in this parameter
-d - JSON dataMultiple data files can be passed, as in -r parameter:
ajv -s test/schema.json -d "test/valid*.json"
If some file is invalid exit code will be 1.
-r - referenced schemasThe schema in -s parameter can reference any of these schemas with $ref keyword.
Multiple schemas can be passed both by using this parameter multiple times and with glob patterns. Glob pattern should be quoted and extensions cannot be omitted.
-m - meta-schemasSchemas can use any of these schemas as a meta-schema (that is the schema used in $schema keyword - it is used to validate the schema itself).
Multiple meta-schemas can be passed, as in -r parameter.
-c - custom keywords/formats definitionsYou can pass module(s) that define custom keywords/formats. The modules should export a function that accepts Ajv instance as a parameter. The file name should start with ".", it will be resolved relative to the current folder. The package name can also be passed - it will be used in require as is.
These modules can be written in TypeScript if you have ts-node installed.
For example, you can use -c ajv-keywords to add all keywords from ajv-keywords package or -c ajv-keywords/keywords/typeof to add only typeof keyword.
--errors=: error reporting format. Possible values:
js (default): JavaScript objectjson: JSON with indentation and line-breaksline: JSON without indentation/line-breaks (for easy parsing)text: human readable error messages with data paths--changes=: detect changes in data after validation.
Data can be modified with Ajv options --remove-additional, --use-defaults and --coerce-types).
The changes are reported in JSON-patch format (RFC6902).
Possible values are js (default), json and line (see --errors option).
This command validates and compiles schema without validating any data.
It can be used to check that the schema is valid and to create a standalone module exporting validation function(s).
ajv compile -s schema
# compile to module file
ajv compile -s schema -o validate.js
## compile to stdout, to allow code formatting (js-beautify has to be installed separately)
ajv compile -s schema -o | js-beautify > validate.js
-s - file name(s) of JSON-schema(s)Multiple schemas can be passed both by using this parameter multiple times and with glob patterns.
ajv compile -s "test/schema*.json"
-o - output file for compiled validation function moduleIf multiple schemas are compiled with this option the module will have multiple exports named as schema $id's or as file names, otherwise the module will export validation function as default export.
ajv compile -s "schema.json" -o "validate_schema.js"
-o without parameter should be used to output code to stdout to pass it to some code formatter.
This command also supports parameters -r, -m and -c as in validate command.
This command validates and migrates schema from JSON Schema draft-04 to draft-07, draft-2019-09 or draft-2020-12 using json-schema-migrate package.
The version of JSON Schema is determined by --spec parameter (only "draft7", "draft2019" or "draft2020").
ajv migrate -s schema
# compile to specific file name
ajv migrate -s schema -o migrated_schema.json
-s - file name(s) of JSON-schema(s)Multiple schemas can be passed both by using this parameter multiple times and with glob patterns.
ajv migrate -s "test/schema*.json"
If parameter -o is not specified the migrated schema is written to the same file and the original file is preserved with .bak extension.
If migration doesn't change anything in the schema file no changes in files are made.
-o - output file for migrated schemaOnly a single schema can be migrated with this option.
ajv compile -s "schema.json" -o migrated_schema.json
--indent=: indentation in migrated schema JSON file, 4 by default--validate-schema=false: skip schema validationThis command asserts that the result of the validation is as expected.
ajv test -s test/schema.json -d test/valid_data.json --valid
ajv test -s test/schema.json -d test/invalid_data.json --invalid
If the option --valid (--invalid) is used for the test to pass (exit code 0) the data file(s) should be valid (invalid).
This command supports the same options and parameters as validate with the exception of --changes.
You can pass the following Ajv options:
| Option | Description |
|---|---|
| Strict mode | |
--strict= | true/false/log - set all strict mode restrictions |
--strict-schema= | log on (log) or ignore (false) strict restrictions (the default is to log) |
--strict-tuples= | throw on (true) or ignore (false) strict schema restrictions (the default is to throw) |
--strict-types= | throw on (true) or ignore (false) strict types restrictions (the default is to log) |
--strict-required= | throw on (true) or log (log) required properties restrictions (the default is to ignore) |
--allow-matching-properties | allow properties matching patterns in patternProperties |
--allow-union-types | allow union types |
--validate-formats=false | disable format validation |
| Validation and reporting | |
--data | use $data references |
--all-errors | collect all validation errors |
--verbose | include schema and data in errors |
--comment | log schema $comments |
--inline-refs= | referenced schemas compilation mode (true/false/<number>) |
| Modify validated data | |
--remove-additional | remove additional properties (true/all/failing) |
--use-defaults | replace missing properties/items with the values from default keyword |
--coerce-types | change type of data to match type keyword |
| Advanced | |
--multiple-of-precision | precision of multipleOf, pass integer number |
--messages=false | do not include text messages in errors |
--loop-required= | max size of required to compile to expression (rather than to loop) |
--loop-enum= | max size of enum to compile to expression (rather than to loop) |
--own-properties | only validate own properties (not relevant for JSON, but can have effect for JavaScript objects) |
| Code generation | |
--code-es5 | generate ES5 code |
--code-lines | generate multi-line code |
--code-optimize= | disable optimization (false) or number of optimization passes (1 pass by default) |
--code-formats= | code to require formats object (only needed if you generate standalone code and do not use ajv-formats) |
Options can be passed using either dash-case or camelCase.
See Ajv Options for more information.
See https://github.com/ajv-validator/ajv-cli/releases
FAQs
Command line interface for Ajv JSON schema validator
We found that ajv-cli demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 2 open source maintainers collaborating on the project.
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