Added the new keywords from draft 2019-09:

• unevaluatedProperties and unevaluatedItems (require option unevaluated to be supported). Please note that an additional generated code may be added to track evaluated properties, even if these keywords are not used).
• dependentProperties and dependentSchemas (require option next to be supported). These keywords replaced dependencies that is still supported though for draft-7 compatibility.
• maxContains and minContains (require option next to be supported). See docs and examples here

• Export additional types
• Prevent optimiser from removing assignments with side effects when (for user keywords that modify data and have valid: true option)
• This version is compatible with ajv-keywords v4.0.0-beta.0 and ajv-formats v0.4.0

See v7.0.0-beta.0 for changes from v6.

Switched to syntax tree for code generation.

Added code optimizations:

• removes empty and unreachable branches.
• removes unused variable declarations.
• replaces variables that are used only once and assigned expressions that are explicitly marked as "constant" (i.e. having referential transparency) with the expressions themselves.

These optimizations reduce the size of generated code by more than 10% (based on the tests), removing over 16% of statements in compiled code.

Option code.optimize to control optimization - one optimization pass by default.

See Code optimization for more details.

Please note - this document covers the changes from Ajv v6.

The current latest beta version is v7.0.0-beta.4 - see the releases beta.1-beta.4 in addition to the below.

The main changes

• to reduce the mistakes in JSON schemas and unexpected validation results, strict mode is added - it prohibits ignored or ambiguous JSON Schema elements. See Strict mode and Options for more details
• to make code injection from untrusted schemas impossible, code generation is fully re-written to be type-level safe against code injection via untrusted schemas.
• to simplify Ajv extensions, the new keyword API that is used by pre-defined keywords is available to user-defined keywords - it is much easier to define any keywords now, especially with subschemas.
• schemas are compiled to ES6 code (ES5 code generation is supported with an option).
• to improve reliability and maintainability the code is migrated to TypeScript.

Please note:

• the support for JSON-Schema draft-04 is removed - if you have schemas using "id" attributes you have to replace them with "$id" (or continue using version 6 that will be supported until 02/28/2021).
• all formats are separated to ajv-formats package - they have to be explicitly added if you use them.

Better TypeScript support:

• Methods compile and compileAsync now return type-guards - see Getting started.
• Method validate is a type-guard.
• Better separation of asynchronous schemas on type level.
• Type utility JSONSchemaType<T> that generates the type for JSON Schema for type interface in the type parameter - it simplifies writing schemas (no unions support at the moment).

API changes:

• addVocabulary - NEW method that allows to add an array of keyword definitions.
• addKeyword - keyword name should be passed as property in definition object, not as the first parameter (old API works with "deprecated" warning). Also "inline" keywords support is removed, code generation keywords can now be defined with "code" keyword - the same definition format that is used by all pre-defined keywords
• Ajv no longer allows to create the instance without new keyword (it is ES6 class).

Added options (and defaults):

• strict: true - strict mode
• strictTypes: "log" - prevent mistakes related to type keywords and keyword applicability (see Strict Types)
• strictTuples: "log" - prevent incomplete tuple schemas (see Prohibit unconstrained tuples)
• allowUnionTypes: false - allow multiple non-null types in "type" keyword
• allowMatchingProperties: false - allow overlap between "properties" and "patternProperties" keywords
• loopEnum: Infinity - optimise validation of enums, similar to loopRequired
• validateFormats: true - enable format validation

Changed options:

• keywords - now expects the array of keyword definitions (old API works with "deprecated" warning)

Removed options:

• errorDataPath - was deprecated, now removed.
• format - validateFormats: false can be used instead, old format mode can be chosen via ajv-formats package.
• nullable: nullable keyword is supported by default.
• jsonPointers: JSONPointers are used to report errors by default, jsPropertySyntax: true (deprecated) can be used if old format is needed.
• extendRefs: $ref siblings are validated by default (consistent with draft 2019-09), ignoreKeywordsWithRef (deprecated) can be used instead to ignore $ref siblings.
• missingRefs: now exception is always thrown. Pass empty schema with $id that should be ignored to ajv.addSchema.
• processCode: replaced with code: {process: (code, schemaEnv: object) => string}.
• sourceCode: replaced with code: {source: true}.
• schemaId: removed, as JSON Schema draft-04 is no longer supported.
• strictDefaults, strictKeywords, strictNumbers: it is default now, controlled with strict.
• uniqueItems: '"uniqueItems" keyword is always validated.
• unknownFormats: the same can be achieved by passing true for formats that need to be ignored via ajv.addFormat or formats option.
• cache and serialize: Map is used as cache, schema object as key.

Pre-release of Ajv v7-beta version that is due end of September.

Unless you want to experiment with the new version, it is recommended to continue using v6 until the following releases with proper release notes.

This release is needed to update related package(s).

Fix performance issue of "url" format.

Fix uri scheme validation (@ChALkeR). Fix boolean schemas with strictKeywords option (#1270)

Fix: coercion of one-item arrays to scalar that should fail validation (failing example).

Pass schema object to processCode function Option for strictNumbers (@issacgerges, #1128) Fixed vulnerability related to untrusted schemas (CVE-2020-15366)

Improved hostname validation (@sambauers, #1143) Option keywords to add custom keywords (@franciscomorais, #1137) Types fixes (@boenrobot, @MattiAstedrone) Docs:

• error logging example (@RadiationSickness)
• TypeScript usage notes (@thetric)

Time formats support two digit and colon-less variants of timezone offset (#1061 , @cjpillsbury) Docs: RegExp related security considerations Tests: Disabled failing typescript test

Fix: the unknown keywords were ignored with the option strictKeywords: true (instead of failing compilation) in some sub-schemas (e.g. anyOf), when the sub-schema didn't have known keywords.

Fix types Fix addSchema (#1001) Update dependencies

Option strictDefaults to report ignored defaults (#957, @not-an-aardvark) Option strictKeywords to report unknown keywords (#781)

OpenAPI keyword nullable can be any boolean (and not only true). Custom keyword definition changes:

• dependencies option in to require the presence of keywords in the same schema.
• more strict validation of the definition using JSON Schema.

Docs: security considerations. Meta-schema for the security assessment of JSON Schemas.

Option useDefaults: "empty" to replace null and "" (empty strings) with default values (in addition to assigning defaults to missing and undefined properties). Update draft-04 meta-schema to remove incorrect usage of "uri" format.

Keyword "nullable" from OpenAPI spec Replaced phantomjs with headless chrome

With option passContext, the context is now passed in recursive/mutually recursive refs (@cvlab, #768).

Support URNs in $id - core url package is replaced with url-js (#423, @sondrele).

Typescript declarations updated to use PromiseLike (#717, @krenor)

Parameter allowedValue in the error of const keyword (#713, @marshall007).

A different error message for additionalProperties error with errorDataPath: 'property' option (#671, @lehni)

Changes from v5.5.2

draft-07 support:

• if/then/else keywords
• $comment keyword
• default meta-schema is draft-07

Schema IDs

• only $id keyword is used as schema ID by default.
• schemaId option should be set to "id" or "auto" for id keyword to be used. See Options.

Formats

• date, date-time, time: support leap year and leap second
• json-pointer: only validates a string format of JSON pointer
• json-pointer-uri-fragment: to validate uri-fragment format of JSON pointer

Keyword changes

• Improved algorithm for uniqueItems keyword to validate an array of same-type scalars in one pass
• Keywords uniqueItems and contains are validated after items and type coercion (with coerceTypes option)
• Additional error parameters for oneOf keyword
• Removed deprecated patternGroups keyword
• Reserved annotation keywords: examples, readOnly, writeOnly, contentEncoding, contentMediaType.

Other

• Defaults are now assigned inside schemas of then/else keywords.
• Option $comment to log/pass to a function strings from $comment keyword.
• Async schemas can only be compiled to async functions, compilation to generator functions is no longer supported.
• Documented convention for plugins.
• Removed v5 meta-schema.
• Removed nodent bundle, ajv-async bundle includes nodent now.

Only $id keyword is used as schema ID by default. schemaId option should be set to "id" or "auto" for id keyword to be used. See Options.

Changes from v5.4.0 and v5.5.0. Defaults are now assigned inside schemas of then/else keywords. Removed deprecated patternGroups keyword and v5 meta-schema.

Option $comment to log/pass to a function strings from draft-07 $comment keywords. Removed nodent bundle, ajv-async bundle includes nodent now. Reserved annotation keywords: examples, readOnly, writeOnly, contentEncoding, contentMediaType.

draft-07 support:

• if/then/else keywords
• $comment keyword (reserved)
• default meta-schema is draft-07

Formats:

• date, date-time, time: support leap year and leap second
• json-pointer: only validates a string format of JSON pointer
• json-pointer-uri-fragment: to validate uri-fragment format of JSON pointer

Keyword changes

• Improved algorithm for uniqueItems keyword to validate an array of same-type scalars in a single pass
• Keywords uniqueItems and contains are validated after items and type coercion (with coerceTypes option)
• Additional error parameters for oneOf keyword

Other

• Async schemas can only be compiled to async functions, compilation to generator functions is no longer supported.
• Documented convention for plugins.

Support chaining of methods add* and remove* (#625, @pithu), see Api.

Option logger to disable logging or to specify a custom logger (#618, @meirotstein).

Replace json-stable-stringify with a faster fork without jsonify.

Refactor: separate "equal" into package fast-deep-equal