REST Data Validator

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Validation Library Guide ​

Overview ​

This library provides a comprehensive set of validation schemas to validate various data types and structures in a scalable and flexible manner. Below is the detailed documentation for each schema type available in the library.

Table of Contents ​

StringSchema ​

Description ​

The StringSchema validates string values and allows setting constraints like minimum and maximum length.

Usage ​

typescript
const schema = SchemaValidator.string().min(3).max(10).required(true);

Example ​

typescript
const validationResult = schema.validate('example');
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

NumberSchema ​

Description ​

The NumberSchema validates number values and allows setting constraints like minimum and maximum value.

Usage ​

typescript
const schema = SchemaValidator.number().min(18).max(65);

Example ​

typescript
const validationResult = schema.validate(25);
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

BooleanSchema ​

Description ​

The BooleanSchema validates boolean values.

Usage ​

typescript
const schema = SchemaValidator.boolean().required(true);

Example ​

typescript
const validationResult = schema.validate(true);
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

ObjectSchema ​

Description ​

The ObjectSchema validates objects based on a schema definition for each property.

Usage ​

typescript
const schema = SchemaValidator.object({
  name: SchemaValidator.string().min(3).max(30),
  age: SchemaValidator.number().min(18),
});

Example ​

typescript
const validationResult = schema.validate({ name: 'John', age: 25 });
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

ArraySchema ​

Description ​

The ArraySchema validates arrays and allows setting constraints on the array's length and its elements' schema.

Usage ​

typescript
const schema = SchemaValidator.array(SchemaValidator.string().min(2).max(20));

Example ​

typescript
const validationResult = schema.validate(['hello', 'world']);
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

UnionSchema ​

Description ​

The UnionSchema validates a value that can match any one of the provided schemas.

Usage ​

typescript
const schema = SchemaValidator.union([SchemaValidator.string(), SchemaValidator.number()]);

Example ​

typescript
const validationResult = schema.validate(42);
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

EnumSchema ​

Description ​

The EnumSchema validates a value that is one of a predefined set of allowed values.

Usage ​

typescript
const schema = SchemaValidator.enum(['red', 'green', 'blue']);

Example ​

typescript
const validationResult = schema.validate('green');
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

DateSchema ​

Description ​

The DateSchema validates date values and allows setting constraints on the date range.

Usage ​

typescript
const schema = SchemaValidator.date().min(new Date('2020-01-01')).max(new Date());

Example ​

typescript
const validationResult = schema.validate(new Date('2022-01-01'));
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

TupleSchema ​

Description ​

The TupleSchema validates an array with a fixed length and specific types at each index.

Usage ​

typescript
const schema = SchemaValidator.tuple([SchemaValidator.string(), SchemaValidator.number()]);

Example ​

typescript
const validationResult = schema.validate(['hello', 42]);
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

RecordSchema ​

Description ​

The RecordSchema validates an object where all keys must match a schema and all values must match another schema.

Usage ​

typescript
const schema = SchemaValidator.record(SchemaValidator.string(), SchemaValidator.number());

Example ​

typescript
const validationResult = schema.validate({ a: 1, b: 2 });
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

NullableSchema ​

Description ​

The NullableSchema allows a value to be null or to satisfy another schema.

Usage ​

typescript
const schema = SchemaValidator.nullable(SchemaValidator.string().min(3));

Example ​

typescript
const validationResult = schema.validate(null);
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

AnySchema ​

Description ​

The AnySchema accepts any value without restrictions.

Usage ​

typescript
const schema = SchemaValidator.any();

Example ​

typescript
const validationResult = schema.validate(123);
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

LazySchema ​

Description ​

The LazySchema allows defining a schema that is evaluated lazily, useful for recursive or conditional schemas.

Usage ​

typescript
const recursiveSchema = new LazySchema(() =>
  SchemaValidator.object({
    name: SchemaValidator.string(),
    children: SchemaValidator.array(new LazySchema(() => recursiveSchema)).optional(),
  })
);

Example ​

typescript
const validationResult = recursiveSchema.validate({
  name: 'parent',
  children: [{ name: 'child' }],
});
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

LiteralSchema ​

Description ​

The LiteralSchema validates that a value matches a specific literal value.

Usage ​

typescript
const schema = SchemaValidator.literal('specificValue');

Example ​

typescript
const validationResult = schema.validate('specificValue');
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

TransformSchema ​

Description ​

The TransformSchema allows transforming the value during validation, applying a transformation function before validating.

Usage ​

typescript
const schema = SchemaValidator.transform(SchemaValidator.string().min(3), value => value.trim());

Example ​

typescript
const validationResult = schema.validate('   hello   ');
console.log(validationResult.isValid); // true
console.log(validationResult.errors);  // []

Summary ​

This documentation provides a comprehensive overview of all the available validation schemas in the library. Each schema is designed to be flexible and reusable, enabling developers to build complex validation logic easily.

For more detailed examples and use cases, refer to the specific sections above.