vator
Assert validator for TypeScript projects.
Installation
npm install vator
Usage
import { v, validate, buildSchema, is } from 'vator';
const { v, validate, buildSchema, is } = require('vator');
Examples
'is'
is
is a collection of shortcuts for comparing types of values.
The regular
if (value === undefined) {
...
}
can be replaced with more convenient
if (is.undefined(value)) {
...
}
Designed to be used in conditions, because it uses type guard
approach.
const maybeNumber = Math.random() > 0.5 ? 10 : null;
if (is.number(maybeNumber)) {
console.log(maybeNumber + 10);
} else {
console.log(maybeNumber === null);
}
Available is
validators:
is.undefined();
is.null();
is.nullable();
is.string();
is.number();
is.email();
is.phone();
Primitives with 'validate'
Will validate that value
is a string type:
const value = 'some';
validate(value, v.string);
Will throw an error if value is not matching the type:
const value = 22;
validate(value, v.string);
Error:
Validation failed: value has type 'number', but 'string' type is required.
Objects and Arrays with 'validate'
Will validate that value
is an object with described fields.
Also it's more convenient to use buildSchema
helper to get schema
and ResultType
.
Note
ReturnType
is an empty object, only refers to valid result type!.
const value: unknown = {
name: 'some-name',
age: 100,
isOnline: false,
updatedAt: '2023-05-22T14:32:34.324Z',
unknownData: [2, 'foo', false]
cars: [
{
model: 'bmw',
year: 2017
},
{
model: 'audi',
year: null
}
]
};
const { schema, ResultType } = buildSchema({
name: v.string,
age: v.optional.number,
isOnline: v.maybe.boolean,
updatedAt: v.Date,
unknownData: v.unknown,
cars: v.array(v.object({
model: v.literal('bmw', 'audi'),
year: v.nullable.number
}))
});
validate(value, schema)
Also value
will then have valid types (because validate()
asserts them)