json-gate

library0.8.23jsnpmunverified

A friendly, fast JSON schema validator for JavaScript, supporting JSON Schema Draft 3. Current stable version is 0.8.23. The library is minimal and synchronous or asynchronous. It produces detailed, human-friendly error messages. Unlike many modern validators, it only supports Draft 3 (not Draft 4+ or 2020-12), making it a legacy choice. The API is simple: create a schema and validate objects. It is not actively maintained, as the last release was years ago. It has no dependencies.

validation

npm install json-gate

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · JSON-GATE

json-gate

validationjavascriptv0.8.23

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

createSchema

✓ import { createSchema } from 'json-gate'

✗ const createSchema = require('json-gate').createSchema

CommonJS require works but ESM import is preferred for modern projects. The default export is not available.

Schema

✓ import { Schema } from 'json-gate'

✗ import Schema from 'json-gate'

Schema is a named export, not default. You can also create schema via createSchema() which returns a Schema instance.

SchemaError

✓ import { SchemaError } from 'json-gate'

✗ const SchemaError = require('json-gate').SchemaError

SchemaError is thrown on validation failure. It is a named export. In TypeScript, you may need to declare types.

Create a schema, validate an object synchronously, and handle errors.

import { createSchema } from 'json-gate'; const schema = createSchema({ type: 'object', properties: { name: { type: 'string', required: true }, age: { type: 'integer', minimum: 0, default: 0 } }, additionalProperties: false }); const input = { name: 'Alice' }; try { schema.validate(input); console.log('Valid!', input); } catch (err) { console.error('Validation failed:', err.message); }

Debug

Known issues

deprecatedjson-gate only supports JSON Schema Draft 3. Draft 4 and later features (e.g., const, if/then/else) are not supported.

fix

Use a modern validator like Ajv or @cfworker/json-schema.

affects: >=0.0.0

gotchavalidate() mutates the input object when 'default' properties are specified.

fix

Clone the input before validating if mutation is undesirable: schema.validate(JSON.parse(JSON.stringify(input))).

affects: >=0.0.0

gotchavalidate() throws an error synchronously but also accepts a callback for async mode. Mixing them can cause confusion.

fix

Choose one mode consistently. If using callback, pass a function as second argument to avoid exceptions being thrown.

affects: >=0.0.0

breakingThe package has no TypeScript definitions. Using with TypeScript requires manual type declarations.

fix

Install @types/json-gate if available (none exist) or create a declaration file.

affects: >=0.0.0

gotchaThe schema object is mutated during validation if it contains 'default' values that are applied.

fix

Deep clone the schema before use if reuse is needed without defaults applied.

affects: >=0.0.0

Errors

Common errors & fixes

TypeError: json_gate_1.createSchema is not a function

Default import used when named import is required.

fix

Use import { createSchema } from 'json-gate' instead of import createSchema from 'json-gate'.

SchemaError: JSON object property 'age': value 150 is greater than maximum 120

Input violates schema constraint (maximum).

fix

Ensure input values meet schema requirements.

Error: Schema property 'additionalProperties' is not a boolean

Schema definition has invalid type for reserved keyword.

fix

Set 'additionalProperties' to a boolean or a schema object.

TypeError: schema.validate is not a function

createSchema() was not called correctly, or the schema variable is undefined.

fix

Ensure createSchema() is called with a valid schema object and returns a Schema instance.

Upgrade

Version history

0.8.23latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

26 hits · last 30 days

node

Resources

githubhttps://github.com/oferei/json-gate ↗

packagejson-gate ↗

homepagehttps://github.com/oferei/json-gate#readme ↗