ajv passes all the tests from [JSON Schema Test Suite](https://github.com/json-schema/JSON-Schema-Test-Suite) (apart from the one that requires that `1.0` is not an integer).
Benchmark of the test suite - [json-schema-benchmark](https://github.com/ebdrup/json-schema-benchmark).
[Same benchmark](https://github.com/epoberezkin/json-schema-benchmark) run on faster CPU with node 0.12.
[Benchmark of individual test cases](https://rawgit.com/zaggino/z-schema/master/benchmark/results.html) by [z-schema](https://github.com/zaggino/z-schema).
ajv compiles schemas to functions and caches them in all cases (using stringified schema as a key - using [json-stable-stringify](https://github.com/substack/json-stable-stringify)), so that the next time the same schema is used (not necessarily the same object instance) it won't be compiled again.
If you need to use ajv in several bundles you can create a separate browserified bundle using `bin/create-bundle` script (thanks to [siddo420](https://github.com/siddo420)).
The following formats are supported for string validation with "format" keyword:
- _date_: full-date from http://tools.ietf.org/html/rfc3339#section-5.6
- _date-time_: date-time from the same source. Both `date` and `date-time` validate ranges in `full` mode and only regexp in `fast` mode (see [options](#options)).
- _uri_: full uri with optional protocol.
- _email_: email address.
- _hostname_: host name acording to http://tools.ietf.org/html/rfc1034#section-3.5
- _ipv4_: IP address v4.
- _ipv6_: IP address v6.
- _regex_: tests whether a string is a valid regular expression by passing it to RegExp constructor.
There are two modes of fomat validation: `fast` and `full` that affect all formats but `ipv4` and `ipv6`. See [Options](#options) for details.
You can find patterns used for format validation and the sources that were used in [formats.js](https://github.com/epoberezkin/ajv/blob/master/lib/compile/formats.js).
Validating function returns boolean and has properties `errors` with the errors from the last validation (`null` if there were no errors) and `schema` with the reference to the original schema.
Unless the option `validateSchema` is false, the schema will be validated against meta-schema and if schema is invalid the error will be thrown. See [options](#options).
Instead of the schema you can use the key that was previously passed to `addSchema`, the schema id if it was present in the schema or any previously resolved reference.
Add schema(s) to validator instance. From version 1.0.0 this method does not compile schemas (but it still validates them). Because of that change, dependencies can be added in any order and circular dependencies are supported. It also prevents unnecessary compilation of schemas that are containers for other schemas but not used as a whole.
- array of schemas can be passed (schemas should have ids), the second parameter will be ignored.
- key can be passed that can be used to reference the schema and will be used as the schema id if there is no id inside the schema. If the key is not passed, the schema id will be used as the key.
By default the schema is validated against meta-schema before it is added, and if the schema does not pass validation the exception is thrown. This behaviour is controlled by `validateSchema` option.
##### .addMetaSchema(Object schema [, String key]) -> Function
Adds meta schema that can be used to validate other schemas. That function should be used instead of `addSchema` because there may be instance options that would compile a meta schema incorrectly (at the moment it is `removeAdditional` option).
There is no need to explicitely add draft 4 meta schema (http://json-schema.org/draft-04/schema) - it is added by default, unless option `meta` is set to `false`. You only need to use it if you have a changed meta-schema that you want to use to validate your schemas. See `validateSchema`.
Validates schema. This method should be used to validate schemas rather than `validate` due to the inconsistency of `uri` format in JSON-Schema standart.
By default this method is called automatically when the schema is added, so you rarely need to use it directly.
Retrieve compiled schema previously added with `addSchema` by the key passed to `addSchema` or by its full reference (id). Returned validating function has `schema` property with the reference to the original schema.
Remove added/cached schema. Even if schema is referenced by other schemas it can be safely removed as dependent schemas have local references.
Schema can be removed using key passed to `addSchema`, it's full reference (id) or using actual schema object that will be stable-stringified to remove schema from cache.
Options can have properties `separator` (string used to separate errors, ", " by default) and `dataVar` (the variable name that dataPaths are prefixed with, "data" by default).
- _removeAdditional_: remove additional properties. Default is not to remove. If the option is 'all', then all additional properties are removed, regardless of `additionalProperties` keyword in schema (and no validation is made for them). If the option is `true` (or truthy), only additional properties with `additionalProperties` keyword equal to `false` are removed. If the option is 'failing', then additional properties that fail schema validation will be removed too (where `additionalProperties` keyword is schema).
- _format_: formats validation mode ('fast' by default). Pass 'full' for more correct and slow validation or `false` not to validate formats at all. E.g., 25:00:00 and 2015/14/33 will be invalid time and date in 'full' mode but it will be valid in 'fast' mode.
- _schemas_: an array or object of schemas that will be added to the instance. If the order is important, pass array. In this case schemas must have IDs in them. Otherwise the object can be passed - `addSchema(value, key)` will be called for each schema in this object.
- _validateSchema_: validate added/compiled schemas against meta-schema (true by default). `$schema` property in the schema can either be absent (draft-4 meta-schema will be used) or can be a reference to any previously added schema. If the validation fails, the exception is thrown. Pass "log" in this option to log error instead of throwing exception. Pass `false` to skip schema validation.
- _missingRefs_: by default if the reference cannot be resolved during compilation the exception is thrown. Pass 'ignore' to log error during compilation and pass validation. Pass 'fail' to log error and successfully compile schema but fail validation if this rule is checked.
- _unicode_: calculate correct length of strings with unicode pairs (true by default). Pass `false` to use `.length` of strings that is faster, but gives "incorrect" lengths of strings with unicode pairs - each unicode pair is counted as two characters.
- _beautify_: format the generated function with [js-beautify](https://github.com/beautify-web/js-beautify) (the validating function is generated without line-breaks). `npm install js-beautify` to use this option. `true` or js-beautify options can be passed.
- _cache_: an optional instance of cache to store compiled schemas using stable-stringified schema as a key. For example, set-associative cache [sacjs](https://github.com/epoberezkin/sacjs) can be used. If not passed then a simple hash is used which is good enough for the common use case (a limited number of statically defined schemas). Cache should have methods `put(key, value)` and `get(key)`.
All validation functions are generated using doT templates in [dot](https://github.com/epoberezkin/ajv/tree/master/lib/dot) folder. Templates are precompiled so doT is not a run-time dependency.
`bin/compile-dots` - compiles templates to [dotjs](https://github.com/epoberezkin/ajv/tree/master/lib/dotjs) folder (please use node 0.10 to compile - 0.12 is fully supported but it inserts some empty comments in function parameters when Function constructor is called).
