ata-validator

Custom keywords. new Validator(schema, { keywords: { name: definition } }) registers keywords with a validate(value, data, parentSchema) function, a compile(value, parentSchema) factory, or a macro(value, parentSchema) that returns a schema applied in place. A definition can name the JSON Schema type it applies to. A schema that uses a registered keyword runs on the interpreted engine, so anyOf, not, $ref and the other applicators keep their meaning around the custom check; the compiled engines, the tier-0 plan and the native walker are routed away from such schemas, and the AOT emitters refuse them instead of emitting a module that would ignore the keyword. See docs/custom-keywords.md.

ata-validator/compat covers the reference class's surface: compileAsync, removeSchema, validateSchema against the vendored meta-schemas, addFormat in its four forms, addKeyword in the validate, compile and macro forms plus the bare-name form, addVocabulary, getKeyword, removeKeyword, errorsText, addMetaSchema, ajv.errors and ajv.opts; and the constructor options allErrors, useDefaults (off by default, as in the reference), coerceTypes, removeAdditional, verbose, validateFormats, validateSchema, formats, keywords and schemas. A schema with no $schema is read as draft-07.

The shim reports errors in the reference's shape and order: keywords in evaluation order rather than declaration order, the failing branches before an anyOf or oneOf, each bad property name with its own errors and a propertyNames error, items before contains and an if error after a failed then/else under allErrors, draft-07 dependencies named as such, and with allErrors off the first failing keyword's whole group. tests/test_ajv_parity.js runs 32 scenarios of real consumer call shapes through both implementations and compares the results field by field.