loudo-check

Check is a small library for adding strict checks to objects.

import { Check } from "loudo-check"

class User extends Check.define({
  id: { v:1, min:1 },
  email:{ v:"[e-mail]", regex:/[a-z0-9]+@[a-z]+\.[a-z]{2,3}/ },
  name:{ v:"Reba", min:1, max:100 }
}) {}

const inputJSON = `
{
  "id":1234,
  "email":"[e-mail]",
  "name":"Flugelhorn"
}
`

const user = Check.parse(User, inputJSON)
const user2 = new User({
  id:1234,
  "email":"[e-mail]",
  "name":"Flugelhorn",
})

Defining Checks

Use Check.define and pass in a schema consisting of various Check.Property objects that define the properties and the checks for that property.

Check.Property consists of the following fields:

• The v field is a sample value for the property that should pass all of its checks. The v field is mandatory; every other field is optional.
• The required field determines whether the property is required. If unspecified, it defaults to true. You can also use the special string value "default"; in that case, if the property is missing, the sample value (defined via v) will be used instead.
• The min field is either the minimum value for the property (for numbers, Dates, and BigInts) or the minimum length/size of an array, arraylike, string, Set, or anything else that has a length or a size property. If unspecified, there is no minimum.
• Similarly, the max field is either a maximum value (inclusive) or a maximum length/size (inclusive.) If unspecified, there is no maximum.
• The allowed field is a set of discrete values that are allowed. If unspecified, all values are allowed (if they pass the other checks.)
• The regex field is a regular expression that the string representation of the property must match. If unspecified, all values are allowed (if they pass the other checks.)
• The integer field specifies whether or not a number property must be a safe integer. If unspecified, it defaults to true. If false, then real numbers, NaN, and infinities are allowed.

Check.define results in a class that consists of all the defined properties. You can use the class to directly construct instances, but the constructor will raise a CheckError if any of the checks you defined on the properties fail.

You can also pass the class to Check.run to see if checks would pass on input values, or to Check.parse to parse json.