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type

Runtime validation and processing of JavaScript types

- Respects language nature and acknowledges its quirks
- Allows coercion in restricted forms (rejects clearly invalid input, normalizes permissible type deviations)
- No transpilation implied, written to work in all ECMAScript 3+ engines

Use case

Validate arguments input in public API endpoints.

_For validation of more sophisticated input structures (as deeply nested configuration objects) it's recommended to consider more powerful schema based utlities (as AJV or @hapi/joi)_

$3

Bulletproof input arguments normalization and validation:

``javascript
const ensureString = require('type/string/ensure')
, ensureDate = require('type/date/ensure')
, ensureNaturalNumber = require('type/natural-number/ensure')
, isObject = require('type/object/is');

module.exports = (path, options = { min: 0 }) {
path = ensureString(path, { errorMessage: "%v is not a path" });
if (!isObject(options)) options = {};
const min = ensureNaturalNumber(options.min, { default: 0 })
, max = ensureNaturalNumber(options.max, { isOptional: true })
, startTime = ensureDate(options.startTime, { isOptional: true });

// ...logic
};
`

$3

`bash
npm install type
`

Utilities

Aside of general ensure validation util, following kind of utilities for recognized JavaScript types are provided:

##### */coerce

Restricted coercion into primitive type. Returns coerced value or null if value is not coercible per rules.

##### */is

Object type/kind confirmation, returns either true or false.

##### */ensure

Value validation. Returns input value (in primitive cases possibly coerced) or if value doesn't meet the constraints throws TypeError .

Each */ensure utility, accepts following options (eventually passed with second argument):

- isOptional - Makes null or undefined accepted as valid value. In such case instead of TypeError being thrown, null is returned.
- default - A value to be returned if null or undefined is passed as an input value.
- errorMessage - Custom error message. Following placeholders can be used:
- %v - To be replaced with short string representation of invalid value
- %n - To be replaced with meaninfgul name (to be passed with name option) of validated value. Not effective if name option is not present
- errorCode - Eventual error code to be exposed on .code error property
- name - Meaningful name for validated value, to be used in error message, assuming it contains %n placeholder
- Error - Alternative error constructor to be used (defaults to TypeError)

$3

#### General utils:

- ensure

#### Type specific utils:

- Value
- value/is
- value/ensure
- Object
- object/is
- object/ensure
- Plain Object
- plain-object/is
- plain-object/ensure
- String
- string/coerce
- string/ensure
- Number
- number/coerce
- number/ensure
- Finite Number
- finite/coerce
- finite/ensure
- Integer Number
- integer/coerce
- integer/ensure
- Safe Integer Number
- safe-integer/coerce
- safe-integer/ensure
- Natural Number
- natural-number/coerce
- natural-number/ensure
- Array Length
- array-length/coerce
- array-length/ensure
- Time Value
- time-value/coerce
- time-value/ensure
- BigInt
- big-int/coerce
- big-int/ensure
- Array Like
- array-like/is
- array-like/ensure
- Array
- array/is
- array/ensure
- Iterable
- iterable/is
- iterable/ensure
- Set
- set/is
- set/ensure
- Map
- map/is
- map/ensure
- Date
- date/is
- date/ensure
- Function
- function/is
- function/ensure
- Constructor
- constructor/is
- constructor/ensure
- Plain Function
- plain-function/is
- plain-function/ensure
- Reg Exp
- reg-exp/is
- reg-exp/ensure
- Thenable
- thenable/is
- thenable/ensure
- Promise
- promise/is
- promise/ensure
- Error
- error/is
- error/ensure
- Prototype
- prototype/is`

$3

$ npm test

[build-image]: https://github.com/medikoo/type/workflows/Integrate/badge.svg
[build-url]: https://github.com/medikoo/type/actions?query=workflow%3AIntegrate
[cov-image]: https://img.shields.io/codecov/c/github/medikoo/type.svg
[cov-url]: https://codecov.io/gh/medikoo/type
[npm-image]: https://img.shields.io/npm/v/type.svg
[npm-url]: https://www.npmjs.com/package/type

Security contact information

To report a security vulnerability, please use the Tidelift security contact. Tidelift will coordinate the fix and disclosure.