@hyperjump/json-schema-core
Advanced tools
JSON Schema Core (JSC) is a framework for building JSON Schema based validators and other tools.
It includes tools for:
$id, $schema, $ref, etc)JSC is designed to run in a vanilla node.js environment, but has no dependencies on node.js specific libraries so it can be bundled for the browser. No compilers, preprocessors, or bundlers are used. JSC includes support for node.js JavaScript (CommonJS and ES Modules), TypeScript, and browsers.
npm install @hyperjump/json-schema-core
When in a browser context, JSC is designed to use the browser's fetch
implementation instead of a node.js fetch clone. The Webpack bundler does this
properly without any extra configuration, but if you are using the Rollup
bundler you will need to include the browser: true option in your Rollup
configuration.
plugins: [
resolve({
browser: true
}),
commonjs()
]
A Schema Document (SDoc) is a structure that includes the schema, the id, and a
JSON Pointer. The "value" of an SDoc is the portion of the schema that the JSON
pointer points to. This allows an SDoc to represent any value in the schema
while maintaining enough context to follow $refs and track the position in the
document.
Schema.add: (schema: object, url?: URI, dialectId?: string) => URI
Load a schema. Returns the identifier for the schema. See the "$id" and "$schema" sections for more details.
Schema.get: (url: URI, contextDoc?: SDoc) => Promise
Fetch a schema. Schemas can come from an HTTP request, a file, or a schema
that was added with Schema.add.
Schema.uri: (doc: SDoc) => URI
Returns a URI including the id and JSON Pointer that represents a value within the schema.
Schema.getAnchorPointer: (doc: SDoc, anchor: string) => any
Get a JSON Pointer for the location in the schema that the anchor refers to.
Schema.value: (doc: SDoc) => any
The portion of the schema the document's JSON Pointer points to.
Schema.typeOf: (doc: SDoc, type: string) => boolean
Determines if the JSON type of the given doc matches the given type
Schema.has: (key: string, doc: SDoc) => Promise
Similar to key in schema.
Schema.step: (key: string, doc: SDoc) => Promise
Similar to schema[key], but returns an SDoc.
Schema.entries: (doc: SDoc) => Promise<[[string, SDoc]]>
Similar to Object.entries, but returns SDocs for values.
Schema.keys: (doc: SDoc) => [string]
Similar to Object.keys.
Schema.map: (fn: (item: Promise, index: integer) => T, doc: SDoc) => Promise<[T]>
A map function for an SDoc whose value is an array.
Schema.length: (doc: SDoc) => number
Similar to Array.prototype.length.
Schema.toSchema: (doc: SDoc, options: ToSchemaOptions) => object
Get a raw schema from a Schema Document.
ToSchemaOptions: object
file:// URIs will be generated
relative to this path.$schema keyword will be omitted.JSC requires that all schemas are identified by at least one URI. There are two
types of schema identifiers, internal and external. An internal identifier is an
identifier that is specified within the schema using $id. An external
identifier is an identifier that is specified outside of the schema. In JSC, an
external identifier can be either the URL a schema is retrieved with, or the
identifier specified when using Schema.add to load a schema.
JSC can fetch schemas from the web or from the file system, but when fetching from the file system, there are limitations for security reasons. If your schema has an identifier with an http scheme (http://example.com), it's not allowed to reference schemas with a file scheme (file:///path/to/my/schemas).
Internal identifiers ($ids) are resolved against the external identifier of
the schema (if one exists) and the resulting URI is used to identify the schema.
All identifiers must be absolute URIs. External identifiers are required to be
absolute URIs and internal identifiers must resolve to absolute URIs.
const { Core, Schema } = require("@hyperjump/json-schema-core");
// Example: Inline schema with external identifier
const schemaJson = {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "string"
}
Schema.add(schemaJson, "http://example.com/schemas/string");
const schema = await Schema.get("http://example.com/schemas/string");
// Example: Inline schema with internal identifier
const schemaJson = {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"$id": "http://example.com/schemas/string",
"type": "string"
}
Schema.add(schemaJson);
const schema = await Schema.get("http://example.com/schemas/string");
// Example: Inline schema with no identifier
const schemaJson = {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "string"
}
Schema.add(schemaJson); // Error: Couldn't determine an identifier for the schema
// Given the following schema at http://example.com/schemas/foo
// {
// "$schema": "https://json-schema.org/draft/2020-12/schema",
// "$id": "http://example.com/schemas/string",
// "type": "string"
// }
// Example: Fetch schema from external HTTP identifier
const schema = await Schema.get("http://example.com/schemas/string");
// Example: Fetch schema from internal identifier
const schema = await Schema.get("http://example.com/schemas/foo");
// Given the following schema at http://example.com/schemas/bar
// {
// "$schema": "https://json-schema.org/draft/2020-12/schema",
// "$id": "string",
// "type": "string"
// }
// Example: Fetch schema from internal identifier resolved against external identifier
const schema = await Schema.get("http://example.com/schemas/string");
// Given the following schema at /path/to/my/schemas/string.schema.json
// {
// "$schema": "https://json-schema.org/draft/2020-12/schema",
// "type": "string"
// }
// Example: Fetch schema from external FILE identifier
const schema = await Schema.get("file:///path/to/my/schemas/string.schema.json");
// Given the following schema at /path/to/my/schemas/string.schema.json
// {
// "$schema": "https://json-schema.org/draft/2020-12/schema",
// "type": "string"
// }
//
// Given the following schema at http://example.com/schemas/baz
// {
// "$schema": "https://json-schema.org/draft/2020-12/schema",
// "$ref": "file:///path/to/my/schemas/string.schema.json"
// }
// Example: Reference file from network context
const schema = await Schema.get("http://example.com/schemas/baz");
await Core.validate(schema); // Error: Can't access file resource from network context
JSC can read schema from the file system or the web, but by default will only
accept these schemas if they have the proper media type. That's Content-Type: application/schema+json for web requests and the .schema.json file extension
for files. That behavior can be modified or added to using MediaType plugins.
Core.addMediaTypePlugin: (contentType: string, plugin: MediaTypePlugin) => void
Add a custom media type handler to support things like YAML or to change the way JSON is supported.
MediaTypePlugin: object
parse: (response: Response, mediaTypeParameters: object) => [SchemaObject, string]
Given a fetch Response object, parse the body of the request. Return the parsed schema and an optional default dialectId.
matcher: (path) => boolean
Given a filesystem path, return whether or not the file should be considered a member of this media type.
Core.addMediaTypePlugin("application/schema+yaml", {
parse: async (response) => [Yaml.parse(await response.text()), undefined],
matcher: (path) => path.endsWith(".schema.yaml")
});
// Given the following schema at http://example.com/schemas/foo
// $schema: 'https://json-schema.org/draft/2020-12/schema'
// type: string
const schema = await Schema.get("http://example.com/schemas/string");
// Given the following schema at /path/to/my/schemas/string.schema.yaml
// $schema: 'https://json-schema.org/draft/2020-12/schema'
// type: string
const schema = await Schema.get("file:///path/to/my/schemas/string.schema.yaml");
JSC is designed to support multiple drafts of JSON Schema and it makes no
assumption about what draft your schema uses. You need to specify it in some
way. The preferred way is to the use $schema in all of your schemas, but you
can also specify what draft to use when adding a schema using Schema.add. If a
draft is specified in Schema.add and the schema has a $schema, the
$schema will be used. If no draft is specified, you will get an error.
// Example: Internal schema version
const schemaJSON = {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"$id": "http://example.com/schemas/string",
"type": "string"
};
Schema.add(schemaJSON);
// Example: External schema version
const schemaJSON = {
"type": "string"
};
Schema.add(schemaJSON, "http://example.com/schemas/string", "https://json-schema.org/draft/2020-12/schema");
// Example: No schema version
const schemaJSON = {
"$id": "http://example.com/schemas/string",
"type": "string"
};
Schema.add(schemaJSON); // Error: Couldn't determine schema version
// Given the following schema at http://example.com/schemas/foo
// {
// "type": "string"
// }
// Example: No schema version external
const schema = Schema.get("http://example.com/schemas/string"); // Error: Couldn't determine schema version
An Instance Document (IDoc) is like a Schema Document (SDoc) except with much more limited functionality.
Instance.cons: (instance: any) => IDoc
Construct a IDoc from a value.
Instance.get: (url: URI, contextDoc: IDoc) => IDoc
Apply a same-resource reference to a IDoc.
Instance.uri: (doc: IDoc) => URI
Returns a URI including the id and JSON Pointer that represents a value within the instance.
Instance.value: (doc: IDoc) => any
The portion of the instance that the document's JSON Pointer points to.
Instance.has: (key: string, doc: IDoc) => any
Similar to key in instance.
Instance.typeOf: (doc: IDoc, type: string) => boolean
Determines if the JSON type of the given doc matches the given type.
Instance.step: (key: string, doc: IDoc) => IDoc
Similar to schema[key], but returns a IDoc.
Instance.entries: (doc: IDoc) => [string, IDoc]
Similar to Object.entries, but returns IDocs for values.
Instance.keys: (doc: IDoc) => [string]
Similar to Object.keys.
Instance.map: (fn: (item: IDoc, index: integer) => T, doc: IDoc) => [T]
A map function for a IDoc whose value is an array.
Instance.reduce: (fn: (accumulator: T, item: IDoc, index: integer) => T, initial: T, doc: IDoc) => T
A reduce function for a IDoc whose value is an array.
Instance.every: (fn: (doc: IDoc, index: integer) => boolean, doc: IDoc) => boolean
An every function for a IDoc whose value is an array.
Instance.some: (fn: (doc: IDoc, index: integer) => boolean, doc: IDoc) => boolean
A some function for a IDoc whose value is an array.
Instance.length: (doc: IDoc) => number
Similar to Array.prototype.length.
Some helper functions are provided to assist in building validation functions.
Core.validate: (schema: SDoc, value: any, outputFormat: OutputFormat = Core.FLAG) => Promise
A curried function that validates a JavaScript value against a schema.
Core.compile: (schema: SDoc) => Promise
Compile a schema to be used interpreted later. A compiled schema is a JSON serializable structure that can be serialized an restored for later use.
Core.interpret: (schema: CompiledSchema, instance: Instance, outputFormat = Core.FLAG) =>
A curried function for validating an instance against a compiled schema.
const { Core, Schema } = require("@hyperjump/json-schema-core");
// Example: Inline schema with external identifier
Schema.add({
"$id": "http://example.com/schemas/string",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "string"
});
const schema = await Schema.get("http://example.com/schemas/string");
// Generate a validation function from a Schema Document
const isString = await Core.validate(schema);
// Validate a value from a Schema Document in one step
const result = await Core.validate(schema, "foo");
// Compile a Schema Document for use later
const compiledSchema = await Core.compile(schema);
// Generate a validation function from a compiled schema
const isString = Core.interpret(compiledSchema);
// Validate an instance from a compiled schema
const result = Core.interpret(compiledSchema, Instance.cons("foo"));
JSC supports all of the standard output formats specified for JSON Schema draft 2019-09 and 2020-12 and is separately configurable for instance validation and meta-validtion.
This implementation does not include the suggested keywordLocation property in
the output unit. I think absoluteKeywordLocation+instanceLocation is
sufficient for debugging and it's awkward for the output to produce JSON
Pointers that potentially won't resolve because they cross schema boundaries.
This implementation includes an extra property in the output unit called
keyword. This is an identifier (URI) for the keyword that was validated. With
the standard output unit fields, we can see what keyword was validated by
inspecting the last segment of the absoluteKeywordLocation property. But,
since JSC can support multiple JSON Schema versions, we would have to pull up
the actual schema to find what draft was used. The schema property gives us
enough information to not have to go back to the schema to know what draft is
being used.
By default JSC will validate all schemas against their meta-schema. However, the only time you really need this is when developing schemas. When JSC is running in a production environment or you are working with third-party schemas that you trust to be correct, you can turn off meta-validation to boost performance.
Core.setMetaOutputFormat: (outputFormat: OutputFormat) => undefined
Set the output format used for schema validation. Default Core.DETAILED
Core.setShouldMetaValidate: (shouldMetaValidate: boolean) => undefined
Turn schema validation on or off. Default true
OutputFormat: An enum of available output formats
const { Core, Schema } = require("@hyperjump/json-schema-core");
// Example: Specify instance validation output format
Schema.add({
"$schema": "https://json-schema.org/draft/2020-12/schema",
"$id": "http://example.com/schemas/string",
"type": "string"
});
const schema = await Schema.get("http://example.com/schemas/string");
const isString = await Core.validate(schema);
const output = isString(42, Core.BASIC); // => {
// "keyword": "https://json-schema.org/draft/2020-12/schema",
// "absoluteKeywordLocation": "http://example.com/schemas/string#",
// "instanceLocation": "#",
// "valid": false,
// "errors": [
// {
// "keyword": "https://json-schema.org/draft/2020-12/schema#type",
// "absoluteKeywordLocation": "http://example.com/schemas/string#/type",
// "instanceLocation": "#",
// "valid": false
// }
// ]
// }
// Example: Specify meta-validation output format
Schema.add({
"$schema": "https://json-schema.org/draft/2020-12/schema",
"$id": "http://example.com/schemas/foo",
"type": "this-is-not-a-valid-type"
});
Core.setMetaOutputFormat(Core.BASIC);
const schema = await Schema.get("http://example.com/schemas/foo");
const isString = await Core.validate(schema); // InvalidSchemaError: {
// "keyword": "https://json-schema.org/draft/2020-12/schema",
// "absoluteKeywordLocation": "https://json-schema.org/draft/2020-12/schema#",
// "instanceLocation": "#",
// "valid": false,
// "errors": [
// {
// "keyword": "https://json-schema.org/draft/2020-12/schema#allOf",
// "absoluteKeywordLocation": "https://json-schema.org/draft/2020-12/schema#/allOf",
// "instanceLocation": "#",
// "valid": false
// }
// ...
// ]
// }
// Example: Turn off schema validation
Core.setShouldMetaValidate(false);
const schema = await Schema.get("http://example.com/schemas/foo"); // Load invalid schema
const isString = await Core.validate(schema); // Schema compilation succeeds even though schema is invalid
JSC emits events that you can subscribe to and work with however your
application needs. For now, the only event is the "result" event that emits
output units every time a keyword is validated. Internally, JSC uses these
events to build standard output formats. Other events can be added when
use-cases are identified for them.
const PubSub = require("pubsub-js");
const { Core, Schema } = require("@hyperjump/json-schema-core");
Schema.add({
"$schema": "https://json-schema.org/draft/2020-12/schema",
"$id": "http://example.com/schemas/string",
"type": "string"
});
const schema = await Schema.get("http://example.com/schemas/string");
const isString = await Core.validate(schema);
const results = [];
const subscriptionToken = PubSub.subscribe("result", (message, result) => {
results.push(result);
});
isString(42);
PubSub.unsubscribe(subscriptionToken);
results; // => [
// {
// "keyword": "https://json-schema.org/draft/2020-12/schema",
// "absoluteKeywordLocation": "http://example.com/schemas/string#",
// "instanceLocation": "#",
// "valid": false
// },
// {
// "keyword": "https://json-schema.org/draft/2020-12/schema#type",
// "absoluteKeywordLocation": "http://example.com/schemas/string#/type",
// "instanceLocation": "#",
// "valid": false
// }
// ]
JSC uses a micro-kernel architecture, so it's highly customizable. Everything is a plugin, even the validation logic. This allows you to use JSC as a framework for building other types of JSON Schema based tools such as code generators or form generators.
In addition to this documentation you should be able to look at the JSV code to see an example of how to add your custom plugins because it's all implemented the same way.
Schema.setConfig: (jsonSchemaVersion: string, configName: string, configValue: string) => undefined
Set a configuration value for a JSON Schema version.
Schema.getConfig: (dialectId: string, configName: string) => any
Get a configuration value for a dialect.
The $ref keyword has changed a couple times over the last several drafts. JSC
allows you to configure which version(s) of $refs you want to support. There
are several types of references.
JSON Reference: (draft-04/06/07) In draft-04, references were defined in
a separate spec from JSON Schema. The JSON Schema spec only constrained $ref
in how URIs are resolved with respect to id. Then in draft-06/07, JSON
Schema absorbed the JSON Reference spec and further constrained $ref to only
be allowed where schemas are allowed. JSC doesn't support this constraint
because it can't be done in a keyword agnostic way.
JSON Schema Reference: (draft-2019-09+) In draft 2019-09, a reference
was changed from being an object with a $ref property to the value of a
$ref keyword. This allowed $ref to behave more like a keyword.
Dynamic JSON Schema Reference: (draft-2019-09+) In draft 2019-09, the concept of a dynamic scope reference was added to make it easier to extend recursive schemas. This was added to support building custom meta-schemas.
Draft-04/6/7 style references are configured via dialect configuration using
Schema.setConfig. Draft-2019-09+ style references are just keywords and can be
added as part of a vocabulary.
const { Schema } = require("@hyperjump/json-schema-core");
// Configure draft-04/6/7 style references
Schema.setConfig("http://json-schema.org/draft-04/schema", "jrefToken", "$ref");
// Configure draft-2019-09+ style references
Core.defineVocabulary("https://example.com/draft/custom/vocab/core", {
"$ref": Keywords.ref,
"$dynamicRef": Keywords.dynamicRef,
...
});
The $id keyword has seen it's fair share of churn as well. Although the spec
around this keyword was rewritten and clarified many times, the vast majority of
changes have simply been name changes. JSC allows you to configure which version
you want to support.
id: (draft-04) A base URI used to resolve reference URIs.
$id: (draft-06/07) Same as id, just a different name.
$id: (draft-2019-09+) Same as $id except with same-document reference
support split out into $anchor.
$anchor: (draft-2019-09+) Same-document reference.
$recursiveAnchor: (draft-2019-09) Dynamic scope same-document reference. Value is a boolean that is only allowed at the root of a schema.
$dynamicAnchor: (draft-2020-12) Dynamic scope same-document reference.
Value is a string and works like $anchor.
In draft-2019-09, $id was redefined from being a resolution scope modifier to
being an inlined reference. This means that JSON Pointers can not cross into
schemas with $ids. So far, JSC only supports these bounded $ids. If I come
up with a way to relax this constraint for old draft implementations, I will,
but since there is no sensible reason to want such a thing, it's a low priority.
In JSON Schema, properties called $id are only considered identifiers if they
appear in a schema. JSC is keyword agnostic, so it doesn't know what is a schema
and what isn't. Therefore, an $id might be treated as an identifier in places
it's not expected to. This is unlikely, but not impossible.
const { Schema } = require("@hyperjump/json-schema-core");
// Configure draft-2019-09+ style identifiers
Schema.setConfig("https://json-schema.org/draft/2020-12/schema", "baseToken", "$id");
Schema.setConfig("https://json-schema.org/draft/2002-12/schema", "embeddedToken", "$id");
Schema.setConfig("https://json-schema.org/draft/2020-12/schema", "anchorToken", "$anchor");
Schema.setConfig("https://json-schema.org/draft/2020-12/schema", "recursiveAnchorToken", "$recursiveAnchor");
// Configure draft-06/7 style references
Schema.setConfig("http://json-schema.org/draft-04/schema", "baseToken", "$id");
Schema.setConfig("http://json-schema.org/draft-04/schema", "embeddedToken", "$id");
Schema.setConfig("http://json-schema.org/draft-04/schema", "anchorToken", "$id");
// Configure draft-04 style references
Schema.setConfig("http://json-schema.org/draft-04/schema", "baseToken", "id");
Schema.setConfig("http://json-schema.org/draft-04/schema", "embeddedToken", "id");
Schema.setConfig("http://json-schema.org/draft-04/schema", "anchorToken", "id");
Let's say you want to use a custom meta-schema that does stricter validation than the standard meta-schema. Once you have your custom meta-schema ready, it's just a couple lines of code to start using it.
const { Core, Schema } = require("@hyperjump/json-schema-core");
// Optional: Load your meta-schema. If you don't do this, JSC will fetch it
// using it's identifier when it's needed.
Schema.add({
"$id": "https://example.com/draft/2020-12-strict/schema",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"$vocabulary": {
"https://json-schema.org/draft/2020-12/vocab/core": true,
"https://json-schema.org/draft/2020-12/vocab/applicator": true,
"https://json-schema.org/draft/2020-12/vocab/validation": true,
"https://json-schema.org/draft/2020-12/vocab/meta-data": true,
"https://json-schema.org/draft/2020-12/vocab/format-annotation": true,
"https://json-schema.org/draft/2020-12/vocab/content": true
},
...
});
// Use the URI you chose for your meta-schema for the `$schema` in you schemas.
Schema.add({
"$id": "http://example.com/schemas/string",
"$schema": "http://example.com/draft/2020-12-strict/schema",
"type": "string"
});
const schema = await Schema.get("http://example.com/schemas/string");
await Core.validate(schema, "foo");
A keyword implementation is a module with at least the functions: compile and
interpret. In the compile step, you can do any processing steps necessary to
do the actual validation in the interpret step. The most common things to do
in the compile step is to follow references and compile sub-schemas. The
interpret step takes the result of the compile step and returns a boolean
value indicating whether validation has passed or failed.
If your custom keyword is an applicator and your dialect supports
unevaluatedProperties and unevaluatedItems, you'll also need to provide the
collectEvaluatedProperties and collectEvaluatedItems functions.
You can Use the JSV keyword implementations as examples when creating your own keywords.
Core.getKeyword: (keywordId: string) => Keyword
Retreive a keyword by it's identifier.
Core.hasKeyword: (keywordId: string) => boolean
Query whether a keyword implementation exists.
Core.compileSchema: (schema: SDoc, ast: AST) => undefined
Compile a schema.
Core.interpretSchmea: (schemaUri: string, instance: Instance, ast: AST, dynamicAnchors: Map[anchor: String, uri: String]) => boolean
Finds the compiled schema in the ast for the schemaUri and validates the instance against the it. The result is a boolean indicating if the keyword passes validation.
Core.collectEvaluatedProperties: (schemaUri: string, instance: Instance, ast: AST, dynamicAnchors: Map[anchor: String, uri: String]) => string[]
Walk a schema and collect any property names that are evaluated by the schemas it finds. A property is not considered evaluated if the schema containing it is not valid.
Core.collectEvaluatedItems: (schemaUri: string, instance: Instance, ast: AST, dynamicAnchors: Map[anchor: String, uri: String]) => number
Walk a schema and collect maximum number of items that are evaluated by the schemas it finds. An item is not considered evaluated if the schema containing it is not valid.
This example implements an if/then/else-like keyword called cond.
cond is an array of schemas where the first is the if schema, the second is
the then schema, and the third is the else schema.
const { Core, Schema } = require("@hyperjump/json-schema-core");
module.exports = {
compile: async (schema, ast) => {
const schemas = await Schema.map((schema) => Core.compileSchema(schema, ast), schema);
return Promise.all(schemas);
},
interpret: (cond, instance, ast, dynamicAnchors) => {
return Core.interpretSchema(cond[0], instance, ast, dynamicAnchors)
? (cond[1] ? Core.interpretSchema(cond[1], instance, ast, dynamicAnchors) : true)
: (cond[2] ? Core.interpretSchema(cond[2], instance, ast, dynamicAnchors) : true);
},
collectEvaluatedProperties: (cond, instance, ast, dynamicAnchors) => {
const propertyNames = Core.collectEvaluatedProperties(cond[0], instance, ast, dynamicAnchors);
const branch = propertyNames ? 1 : 2;
if (cond[branch]) {
const branchPropertyNames = Core.collectEvaluatedProperties(cond[branch], instance, ast, dynamicAnchors);
return branchPropertyNames && (propertyNames || []).concat(branchPropertyNames);
} else {
return propertyNames || [];
}
},
collectEvaluatedItems: (cond, instance, ast, dynamicAnchors) => {
const evaluatedIndexes = Core.collectEvaluatedItems(cond[0], instance, ast, dynamicAnchors);
const branch = evaluatedIndexes !== false ? 1 : 2;
if (cond[branch]) {
const branchEvaluatedIndexes = Core.collectEvaluatedItems(cond[branch], instance, ast, dynamicAnchors);
return branchEvaluatedIndexes !== false && new Set([...evaluatedIndexes || new Set(), ...branchEvaluatedIndexes]);
} else {
return evaluatedIndexes || new Set();
}
}
};
In order to use an keyword in an implementation, you need to add it to a vocabulary.
A vocabulary is just a named collection of keywords.
Core.defineVocabulary: (vocabularyId: string, keywords: { [keywordId]: Keyword }) => undefined
Define a vocabulary giving it an identifier and an object that maps keyword identifiers to keyword implementations.
const { Core, Schema } = require("@hyperjump/json-schema-core");
const cond = require("./keywords/cond");
// Choose a URI for your vocabulary and add keywords
Core.defineVocabulary("https://example.com/draft/custom/vocab/conditionals", {
cond: cond
});
// Create a new meta-schema an add your vocabulary to `$vocabulary`
Schema.add({
"$id": "https://example.com/draft/custom/schema",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"$vocabulary": {
...
"https://example.com/draft/custom/vocab/conditionals": true
},
...
});
// Try it out
Schema.add({
"$id": "http://example.com/schemas/cond-example",
"$schema": "https://example.com/draft/custom/schema",
"type": "integer",
"cond": [
{ "minimum": 10 },
{ "multipleOf": 3 },
{ "multipleOf": 2 }
]
});
const schema = await Schema.get("http://example.com/schemas/cond-example");
await Core.validate(schema, 42);
Run the tests
npm test
Run the tests with a continuous test runner
npm test -- --watch
FAQs
A framework for building JSON Schema tools
The npm package @hyperjump/json-schema-core receives a total of 38,853 weekly downloads. As such, @hyperjump/json-schema-core popularity was classified as popular.
We found that @hyperjump/json-schema-core demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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