Add Support for JSON Schema Draft-04 Keywords #130

srivastava-diya · 2026-01-16T09:40:07Z

Added Support for JSON Schema Draft-04 Keywords

I have implemented full support for the requested Draft-04 keywords in @hyperjump/json-schema-errors.
Issue : #119

Changes made

`items` and `additionalItems`

Draft-04 treats items and additionalItems as siblings where additionalItems validation depends on items (if items is an array).

Implementation: Implemented a items normalization handler in items.js.
The items handler infers the URI of the sibling additionalItems keyword (by string manipulation of the items URI) and retrieves the schema from the AST. It then acts as the validator for the "tail" items that fall under additionalItems criteria.

`dependencies`

Implemented dependencies.js to handle both:

Schema Dependencies: Delegating validation to the dependent schema.
Property Dependencies: Checking for missing required properties (handled in error handler).

Numeric Keywords (`maximum`, `minimum`)

Implemented handlers maximum.js, minimum.js.

These keywords depend on keywords like exclusiveMaximum (boolean).
The error handlers navigate up the schema URI hierarchy to retrieve the parent schema and check the sibling values (e.g. exclusiveMaximum) to construct the correct error message ("less than" vs "less than or equal to").

Also Added test cases

Signed-off-by: Diya <diyasrivastava2023@gmail.com>

srivastava-diya · 2026-01-16T10:18:39Z

@jdesrosiers please have a look whenever you're free,because i feel a lot of it needs to be re iterated over

jdesrosiers

This is a quick review. I didn't have enough time to look over everything in much detail.

Make sure you're working with @Adityakumar37 on the items/additionalItems keywords. I'm hoping to merge that PR first, then you can rebase and add the rest of the draft-04 implementation on top of that.

Anyway, your approach for those keywords isn't right. Those are simple applicators. Simple applicators don't need error handlers. Your normalization handlers should look a lot like the keywords from draft-2020-12 that serve the same purpose.

dependencies is a weird one because it's a simple applicator in some cases (schemas) and a validation keyword in other cases (string array). It can even do both at the same time. I need to go through that handler closer later, but it seems like it should be a problem.

jdesrosiers · 2026-01-18T06:05:18Z

src/error-handlers/draft-04/maximum.js

+    const parentUri = schemaLocation.replace(/\/[^/]+$/, "");
+    const parentSchema = await getSchema(parentUri);
+    const parentValue = /** @type {import("../../index.d.ts").JsonObject} */ (Schema.value(parentSchema));
+    const exclusiveMaximum = /** @type boolean | undefined */ (parentValue.exclusiveMaximum);


This doesn't work in some cases when references are used. See the solution I used for minContains/maxContains in the contains handler for a better approach.

jdesrosiers · 2026-01-18T06:06:36Z

src/error-handlers/draft-04/dependencies.js

+          errors.push({
+            message: localization.getRequiredErrorMessage(missing),
+            instanceLocation: Instance.uri(instance),
+            schemaLocations: [`${schemaLocation}/${propertyPointer}`]


Just use schemaLocation here. You don't need a more specific pointer.

jdesrosiers · 2026-01-18T06:12:49Z

src/normalization-handlers/draft-04/additionalItems.js

+/** @type NormalizationHandler<any> */
+const additionalItemsNormalizationHandler = {
+  evaluate(_params, _instance, _context) {
+    return [];


Returning an empty array never makes sense. This should look a lot like draft-2020-12 items.

jdesrosiers · 2026-01-19T04:37:13Z

src/error-handlers/draft-04/dependencies.js

+    const keywordOutput = dependenciesErrors[schemaLocation];
+    if (Array.isArray(keywordOutput)) {
+      for (const output of keywordOutput) {
+        const result = await getErrors(output, instance, localization);
+        errors.push(...result);
+      }
+    }


Oh, this is how you got around the problem of dependencies being an applicator and a validator. I hadn't intended to use getErrors for this kind of thing, but it makes sense. 👍

Signed-off-by: Diya <diyasrivastava2023@gmail.com>

srivastava-diya · 2026-01-19T04:45:22Z

hey @jdesrosiers ,
i have re-written a few normalization handlers in order to closely resemble some draft-2020-12 handlers. and foe the error handlers i think we only need it for dependencies , maximum, and minimum i have also changed them a bit and at the same time i am waiting for aditya's PR in order to rebase and work on top of those changes.

jdesrosiers

Looks pretty close now. The only thing I haven't looked at yet is the tests.

src/error-handlers/draft-04/dependencies.js

jdesrosiers · 2026-01-19T18:00:20Z

src/error-handlers/draft-04/maximum.js

+    const parentLocation = schemaLocation.replace(/\/maximum$/, "");
+    const parent = await getSchema(parentLocation);
+    const exclusiveNode = await Schema.step("exclusiveMaximum", parent);
+    const exclusive = /** @type boolean */ (Schema.value(exclusiveNode) ?? false);


This won't always work. You have to find the value using the keyword URI, not the keyword name. See the contains error handler for an example.

Actually, contains isn't quite right either because it considers values from other schemas applied to the same location. You're going to have find a solution that doesn't hardcode the keyword name, but only considers keywords in the same subschema.

jdesrosiers · 2026-01-19T18:42:54Z

src/error-handlers/draft-04/maximum.js

+      });
+    } else {
+      errors.push({
+        message: localization.getMaximumErrorMessage(maximum),


While testing I noticed that the messages for exclusiveMaximum and maximum are the same. This PR seems like a good opportunity to fix that.

src/normalization-handlers/draft-04/dependencies.js

srivastava-diya added 4 commits January 11, 2026 06:28

fix: allow numeric values for count and matchCount params

3484d38

drop null and boolean in the schema/type

2cceff6

Merge branch 'hyperjump-io:main' into main

534bdec

draft-04 support

63de3f7

Signed-off-by: Diya <diyasrivastava2023@gmail.com>

jdesrosiers reviewed Jan 18, 2026

View reviewed changes

jdesrosiers reviewed Jan 19, 2026

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fix normalization and error handlers

5b17c4d

Signed-off-by: Diya <diyasrivastava2023@gmail.com>

Merge branch 'hyperjump-io:main' into main

7c44fe3

srivastava-diya changed the title ~~Added Support for JSON Schema Draft-04 Keywords~~ Add Support for JSON Schema Draft-04 Keywords Jan 19, 2026

jdesrosiers reviewed Jan 19, 2026

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srivastava-diya commented Jan 16, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Added Support for JSON Schema Draft-04 Keywords

Changes made

items and additionalItems

dependencies

Numeric Keywords (maximum, minimum)

Also Added test cases

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srivastava-diya commented Jan 16, 2026

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srivastava-diya commented Jan 16, 2026 •

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`items` and `additionalItems`

`dependencies`

Numeric Keywords (`maximum`, `minimum`)