Schema validation for JavaScript
Check that your data has the right shape.
Describe what a value should look like: an API request, a config file, a form. schiva tells you what is wrong with it, field by field, in messages you can show as they are. It is the fastest validator we have measured, and it has no dependencies.
import { ClosedSchema, String, Integer, ArrayOf } from 'schiva';
// 1. Describe the data
const person = new ClosedSchema({
id: String(),
age: Integer({ min: 18 }),
tags: ArrayOf({ type: String(), isMandatory: false }),
});
// 2. Compile it once
const validate = person.compile();
// 3. Validate values
validate({ id: 1, age: 10, extra: 1 });import { compileJsonSchema } from 'schiva';
// 1. Describe the data, 2. compile it once
const validate = compileJsonSchema({
type: 'object',
required: ['id', 'age'],
additionalProperties: false,
properties: {
id: { type: 'string' },
age: { type: 'integer', minimum: 18 },
tags: { type: 'array', items: { type: 'string' } },
},
});
// 3. Validate values
validate({ id: 1, age: 10, extra: 1 });validate() returns the errors ([] when the value is valid):
idmust be a stringagemust be at least 18- Unexpected key:
extra
How it works
Three steps, the same with both ways of writing a schema. Try them with the examples of the playground.
-
1
Describe your data
Write a schema: in JavaScript, with
String(),Integer()...; or in JSON Schema, the standard format that OpenAPI and many tools use. -
2
Compile it once
When your program starts, schiva turns the schema into a JavaScript function written for it. It takes well under a millisecond.
-
3
Validate every value
Call the function with a value. It returns the list of errors, each with the field it is about, or
true/falseif that is all you need.
What it is for
Anywhere data comes from outside your code and you need to trust its shape.
API requests
Reject a bad request body with a 400 and one message per wrong field.
Config files
Stop at startup with a clear message instead of failing later in odd ways.
Forms and user input
Error objects give the path of each field, to show the message next to it.
OpenAPI and JSON Schema
Use the schemas you already have or share: every draft from 04 to 2020-12.
Why schiva
Fast, correct and clear, with nothing else to install.
Fast
Faster than ajv, the most used validator, in every benchmark we run: about twice as fast validating, and more than 40 times faster preparing a schema.
Correct
Passes all 4,950 tests of the official JSON Schema test suite, for the five versions of the standard. No other library we measured passes them all.
Clear errors
Each error names the field and the problem, lines[3].price must be at least 0, ready to
log or return. Error objects are there too, for code.
Two ways to write schemas
A short JavaScript syntax whose TypeScript types are inferred for you, or JSON Schema for schemas you share with other tools and languages.
Safe by default
A typo in a schema, like maxLenght, stops the program when it compiles, instead of being
silently ignored.
Nothing else to install
No dependencies. Runs on Node.js 18 and later and in browsers, even where generating code is not allowed, by writing validators to files when building.
In numbers
Measured against ajv and nine other JSON Schema validators, each in its own process. The details are on the benchmarks page.