README.md
# check-more-types
> Large collection of predicates, inspired by [check-types.js](https://github.com/philbooth/check-types.js)
[![NPM][check-more-types-icon] ][check-more-types-url]
[](https://github.com/bahmutov/manpm)
[![Build status][check-more-types-ci-image] ][check-more-types-ci-url]
[![dependencies][check-more-types-dependencies-image] ][check-more-types-dependencies-url]
[![devdependencies][check-more-types-devdependencies-image] ][check-more-types-devdependencies-url]
[![semantic-release][semantic-image] ][semantic-url]
[![Coverage Status][check-more-types-coverage-image] ][check-more-types-coverage-url]
[![Codacy Badge][check-more-types-codacy-image] ][check-more-types-codacy-url]
[![Code Climate][check-more-types-code-climate-image] ][check-more-types-code-climate-url]
[check-more-types-icon]: https://nodei.co/npm/check-more-types.png?downloads=true
[check-more-types-url]: https://npmjs.org/package/check-more-types
[check-more-types-ci-image]: https://travis-ci.org/kensho-technologies/check-more-types.png?branch=master
[check-more-types-ci-url]: https://travis-ci.org/kensho-technologies/check-more-types
[check-more-types-coverage-image]: https://coveralls.io/repos/kensho-technologies/check-more-types/badge.png
[check-more-types-coverage-url]: https://coveralls.io/r/kensho-technologies/check-more-types
[check-more-types-dependencies-image]: https://david-dm.org/kensho-technologies/check-more-types.png
[check-more-types-dependencies-url]: https://david-dm.org/kensho-technologies/check-more-types
[check-more-types-devdependencies-image]: https://david-dm.org/kensho-technologies/check-more-types/dev-status.png
[check-more-types-devdependencies-url]: https://david-dm.org/kensho-technologies/check-more-types#info=devDependencies
[check-more-types-codacy-image]: https://www.codacy.com/project/badge/25cb5d1410c7497cb057d887d1f3ea23
[check-more-types-codacy-url]: https://www.codacy.com/public/kensho-technologies/check-more-types.git
[check-more-types-code-climate-image]: https://codeclimate.com/github/kensho-technologies/check-more-types/badges/gpa.svg
[check-more-types-code-climate-url]: https://codeclimate.com/github/kensho-technologies/check-more-types
[semantic-image]: https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg
[semantic-url]: https://github.com/semantic-release/semantic-release
See [Readable conditions](http://glebbahmutov.com/blog/readable-conditions-using-check-types/)
for advice and examples.
## Install
**node:** `npm install check-more-types --save`
var check = require('check-more-types');
console.assert(check.bit(1), 'check.bit works');
**browser** `bower install check-more-types --save`
<script src="check-more-types.js"></script>
* **API**
* [check.email](#checkemail)
* [check.extension (alias `check.ext`)](#checkextension-alias-checkext)
* [check.odd and check.even](#checkodd-and-checkeven)
* [check.port](#checkport)
* [check.systemPort](#checksystemport)
* [check.userPort](#checkuserport)
* [check.error](#checkerror)
* [check.https (alias `secure`)](#checkhttps-alias-secure)
* [check.http](#checkhttp)
* [check.webUrl (alias `url`)](#checkweburl-alias-url)
* [check.contains](#checkcontains)
* [check.defined](#checkdefined)
* [check.semver](#checksemver)
* [check.positiveNumber (alias `check.positive`)](#checkpositivenumber-alias-checkpositive)
* [check.negativeNumber (alias `check.negative`)](#checknegativenumber-alias-checknegative)
* [check.type](#checktype)
* [check.bit](#checkbit)
* [check.primitive](#checkprimitive)
* [check.zero](#checkzero)
* [check.git](#checkgit)
* [check.commitId](#checkcommitid)
* [check.shortCommitId](#checkshortcommitid)
* [check.index](#checkindex)
* [check.oneOf](#checkoneof)
* [check.same](#checksame)
* [check.length](#checklength)
* [check.sameLength](#checksamelength)
* [check.allSame](#checkallsame)
* [check.unit](#checkunit)
* [check.hexRgb](#checkhexrgb)
* [check.bool](#checkbool)
* [check.emptyString](#checkemptystring)
* [check.empty](#checkempty)
* [check.unempty](#checkunempty)
* [check.unemptyArray](#checkunemptyarray)
* [check.arrayOfStrings (alias `strings`)](#checkarrayofstrings-alias-strings)
* [check.numbers](#checknumbers)
* [check.arrayOf](#checkarrayof)
* [check.badItems](#checkbaditems)
* [check.arrayOfArraysOfStrings](#checkarrayofarraysofstrings)
* [check.lowerCase](#checklowercase)
* [check.has(obj, property)](#checkhasobj-property)
* [check.all](#checkall)
* [check.schema](#checkschema)
* [check.schema bind](#checkschema-bind)
* [schema composition](#schema-composition)
* [check.raises(fn, validator)](#checkraisesfn-validator)
* [Modifiers](#modifiers)
* [check.maybe](#checkmaybe)
* [check.not](#checknot)
* [check.verify](#checkverify)
* [Adding your own predicates](#adding-your-own-predicates)
* [check.mixin(predicate, name)](#checkmixinpredicate-name)
* [check.mixin does not override](#checkmixin-does-not-override)
* [Defending a function](#defending-a-function)
* [check.defend(fn, predicates)](#checkdefendfn-predicates)
* [protects optional arguments](#protects-optional-arguments)
* [check.defend with messages](#checkdefend-with-messages)
* [check.defend in module pattern](#checkdefend-in-module-pattern)
* [Safe callback execution](#safe-callback-execution)
* [check.then](#checkthen)
* [check.found](#checkfound)
* [check.regexp](#checkregexp)
* [check.promise](#checkpromise)
* [check.validDate](#checkvaliddate)
* [check.equal](#checkequal)
* [check.or](#checkor)
* [check.and](#checkand)
#### check.number
`check.number` is part of the `check-types` library, but as a note, it does not pass
`null`, `undefined` or `NaN` values
```js
check.number(null); // false
check.not.number(undefined); // true
check.number(NaN); // false
```
#### check.email
Really simple regex email check. Should not be relied to be robust.
```js
check.email('me@foo.bar') // true
check.email('me.foo.bar') // false
```
#### check.extension (alias `check.ext`)
Confirms that given file name has expected extension
```js
check.extension('txt', 'foo/bar.txt') // true
```
It is curried, so you can create convenient methods
```js
const isJs = check.extension('js')
isJs('script.js') // true
```
There are a couple of convenient shortcuts, like `check.isJs`, `check.isJson`, `check.isJpg`
#### check.odd and check.even
Check if a number odd or even
```js
check.odd(2) // false
check.odd(3) // true
check.even(2) // true
```
#### check.port
Returns true if passed argument is positive number less or equal to largest
allowed port number 65535
#### check.systemPort
Returns true if passed argument is number between 0 and 1024
#### check.userPort
Returns true if passed argument is a port number and larger than 1024
#### check.error
Returns true if given argument is an instance of type `Error`
#### check.https (alias `secure`)
Returns true if the provided url starts with `https://`. Alias `secure`.
#### check.http
Returns true if the provided url starts with `http://`
#### check.webUrl (alias `url`)
Returns true if the given string is http or https url.
#### check.contains
Returns true if given array contains an item, or given string contains substring.
```js
check.contains(['foo', 42], 'foo'); // true
check.contains('apple', 'pp'); // true
```
#### check.defined
check.defined(0); // true
check.defined(1); // true
check.defined(true); // true
check.defined(false); // true
check.defined(null); // true
check.defined(''); // true
check.defined(); // false
check.defined(root.doesNotExist); // false
check.defined({}.doesNotExist); // false
---
#### check.semver
check.semver('1.0.2'); // true
check.semver('1.0.2-alpha'); // false
---
#### check.positiveNumber (alias `check.positive`)
```js
check.positive(100); // true
check.not.positive(-1); // true
```
---
#### check.negativeNumber (alias `check.negative`)
```js
check.negative(-10); // true
check.not.negativeNumber(1); // true
```
---
#### check.type
check.type('string', 'foo'); // true
check.type('number', 42); // true
`check.type` is curried.
---
#### check.bit
check.bit(0); // true
check.bit(1); // true
check.bit('1'); // false
check.bit(2); // false
check.bit(true); // false
---
#### check.primitive
Returns true for primitive JavaScript types
check.primitive(42); // true
check.primitive(true); // true
check.primitive('foo'); // true
check.primitive([]); // false
Also returns true for `Symbol` ES6 syntax.
---
#### check.zero
check.zero(0); // true
check.zero(); // false
check.zero(null); // false
---
#### check.git
check.git('url string');
---
#### check.commitId
---
#### check.shortCommitId
---
#### check.index
---
#### check.oneOf
var colors = ['red', 'green', 'blue'];
var color = 'green';
check.oneOf(colors, color); // true
check.oneOf(colors, 'brown'); // false
Function is curried
---
#### check.same
var foo = {}
var bar = {}
check.same(foo, foo); // true
check.same(foo, bar); // false
// primitives are compared by value
check.same(0, 0); // true
check.same('foo', 'foo'); // true
`check.same` should produce same result as `===`.
---
#### check.length
Confirms length of a string or an Array. The function is curried and
can guess the argument order
```js
check.length([1, 2], 2); // true
check.length('foo', 3); // true
// argument order
check.length(3, 'foo'); // true
// curried call
check.length('foo')(3); // true
check.length(3)('foo'); // true
```
---
#### check.sameLength
check.sameLength([1, 2], ['a', 'b']); // true
check.sameLength('ab', 'cd'); // true
// different types
check.sameLength([1, 2], 'ab'); // false
---
#### check.allSame
var foo = {}
var bar = {}
check.allSame([foo, foo, foo]); // true
check.allSame([foo, foo, bar]); // false
// primitives are compared by value
check.allSame([0, 0]); // true
check.allSame(['foo', 'foo', 'foo']); // true
check.allSame([false, 0]); // false
---
#### check.unit
check.unit(0); // true
check.unit(1); // true
check.unit(0.1); // true
check.unit(1.2); // false
check.unit(-0.1); // false
---
#### check.hexRgb
check.hexRgb('#FF00FF'); // true
check.hexRgb('#000'); // true
check.hexRgb('#aaffed'); // true
check.hexRgb('#00aaffed'); // false
check.hexRgb('aaffed'); // false
---
#### check.bool
check.bool(true); // true
check.bool(false); // true
check.bool(0); // false
check.bool(1); // false
check.bool('1'); // false
check.bool(2); // false
---
#### check.emptyString
check.emptyString(''); // true
check.emptyString(' '); // false
check.emptyString(0); // false
check.emptyString([]); // false
---
#### check.empty
check.empty([]); // true
check.empty(''); // true
check.empty({}); // true
check.empty(0); // false
check.empty(['foo']); // false
---
#### check.unempty
check.unempty([]); // false
check.unempty(''); // false
check.unempty({}); // false
check.unempty(0); // true
check.unempty(['foo']); // true
check.unempty('foo'); // true
---
#### check.unemptyArray
check.unemptyArray(null); // false
check.unemptyArray(1); // false
check.unemptyArray({}); // false
check.unemptyArray([]); // false
check.unemptyArray(root.doesNotExist); // false
check.unemptyArray([1]); // true
check.unemptyArray(['foo', 'bar']); // true
---
#### check.arrayOfStrings (alias `strings`)
// second argument is checkLowerCase
check.arrayOfStrings(['foo', 'Foo']); // true
check.arrayOfStrings(['foo', 'Foo'], true); // false
check.arrayOfStrings(['foo', 'bar'], true); // true
check.arrayOfStrings(['FOO', 'BAR'], true); // false
---
#### check.numbers
Returns true if all items in an array are numbers
#### check.arrayOf
```js
check.arrayOf(check.unemptyString, ['foo', '']); // false
check.arrayOf(check.unemptyString, ['foo', 'bar']); // true
// can be partially applied and combined with check.schema
var person = {
first: check.unemptyString,
last: check.unemptyString
};
var isPerson = check.schema.bind(null, person);
var arePeople = check.arrayOf.bind(null, isPerson);
var people = [{
first: 'foo',
last: 'bar'
}];
arePeople(people); // true
```
---
Why would you need `check.arrayOf(predicate, x)` and not simply use `x.every(predicate)`?
Because `x` might not be an Array.
#### check.badItems
Finds items that do not pass predicate
```js
check.badItems(check.unemptyString, ['foo', '', 'bar']); // ['']
```
#### check.arrayOfArraysOfStrings
// second argument is checkLowerCase
check.arrayOfArraysOfStrings([['foo'], ['bar'}}); // true
check.arrayOfArraysOfStrings([['foo'], ['bar'}}, true); // true
check.arrayOfArraysOfStrings([['foo'], ['BAR'}}, true); // false
---
#### check.lowerCase
check.lowerCase('foo bar'); // true
check.lowerCase('*foo ^bar'); // true
check.lowerCase('fooBar'); // false
// non-strings return false
check.lowerCase(10); // false
---
#### check.has(obj, property)
var obj = {
foo: 'foo',
bar: 0
}
check.has(obj, 'foo'); // true
check.has(obj, 'bar'); // true
check.has(obj, 'baz'); // false
// non-object returns false
check.has(5, 'foo'); // false
check.has('foo', 'length'); // true
---
#### check.all
var obj = {
foo: 'foo',
bar: 'bar',
baz: 'baz'
}
var predicates = {
foo: check.unemptyString,
bar: function(value) {
return value === 'bar'
}
}
check.all(obj, predicates); // true
---
#### check.schema
var obj = {
foo: 'foo',
bar: 'bar',
baz: 'baz'
}
var schema = {
foo: check.unemptyString,
bar: function(value) {
return value === 'bar'
}
}
check.schema(schema, obj); // true
check.schema(schema, {}); // false
`check.spec` is equivalent to `check.all` but with arguments reversed.
This makes it very convenient to create new validator functions using partial
argument application
The method is curried, thus you can easily create predicate function
```js
var hasName = check.schema({ name: check.unemptyString });
hasName({ name: 'joe' }); // true
```
#### check.schema bind
var personSchema = {
name: check.unemptyString,
age: check.positiveNumber
}
var isValidPerson = check.schema.bind(null, personSchema)
var h1 = {
name: 'joe',
age: 10
}
var h2 = {
name: 'ann'
// missing age property
}
isValidPerson(h1); // true
isValidPerson(h2); // false
If you want you can manually bind `check.schema` to first argument
var personSchema = {
name: check.unemptyString,
age: check.positiveNumber
};
var isValidPerson = check.schema.bind(null, personSchema);
var h1 = {
name: 'joe',
age: 10
};
var h2 = {
name: 'ann'
// missing age property
};
isValidPerson(h1); // true
isValidPerson(h2); // false
You can use `Function.prototype.bind` or any partial application method, for example
`_.partial(check.schema, personSchema);`.
Because bound schema parameter generates a valid function, you can nest checks using
schema composition. For example let us combine the reuse `isValidPerson` as part of
another check
#### schema composition
var teamSchema = {
manager: isValidPerson,
members: check.unemptyArray
}
var team = {
manager: {
name: 'jim',
age: 20
},
members: ['joe', 'ann']
}
check.schema(teamSchema, team); // true
---
#### check.raises(fn, validator)
function foo() {
throw new Error('foo')
}
function bar() {}
function isValidError(err) {
return err.message === 'foo'
}
function isInvalid(err) {
check.instance(err, Error); // true
return false
}
check.raises(foo); // true
check.raises(bar); // false
check.raises(foo, isValidError); // true
check.raises(foo, isInvalid); // false
### Modifiers
Every predicate function is also added to `check.maybe` object.
The `maybe` predicate passes if the argument is null or undefined,
or the predicate returns true.
#### check.maybe
check.maybe.bool(); // true
check.maybe.bool('true'); // false
var empty
check.maybe.lowerCase(empty); // true
check.maybe.unemptyArray(); // true
check.maybe.unemptyArray([]); // false
check.maybe.unemptyArray(['foo', 'bar']); // true
Every function has a negated predicate in `check.not` object
#### check.not
check.not.bool(4); // true
check.not.bool('true'); // true
check.not.bool(true); // false
Every predicate can also throw an exception if it fails
#### check.verify
check.verify.arrayOfStrings(['foo', 'bar'])
check.verify.bit(1)
function nonStrings() {
check.verify.arrayOfStrings(['Foo', 1])
}
check.raises(nonStrings); // true
function nonLowerCase() {
check.verify.lowerCase('Foo')
}
check.raises(nonLowerCase); // true
---
### Adding your own predicates
You can add new predicates to `check`, `check.maybe`, etc. by using `check.mixin(predicate)`
method. If you do not pass a name, it will try using function's name.
#### check.mixin(predicate, name)
function isBar(a) {
return a === 'bar'
}
check.mixin(isBar, 'bar')
check.bar('bar'); // true
check.bar('anything else'); // false
// supports modifiers
check.maybe.bar(); // true
check.maybe.bar('bar'); // true
check.not.bar('foo'); // true
check.not.bar('bar'); // false
Mixin will not override existing functions
#### check.mixin does not override
function isFoo(a) {
return a === 'foo'
}
function isBar(a) {
return a === 'bar'
}
check.mixin(isFoo, 'isFoo')
check.isFoo; // isFoo
check.mixin(isBar, 'isFoo')
check.isFoo; // isFoo
### Defending a function
Using *check-more-types* you can separate the inner function logic from checking input
arguments. Instead of this
```js
function add(a, b) {
la(check.number(a), 'first argument should be a number', a);
la(check.number(a), 'second argument should be a number', b);
return a + b;
}
```
you can use `check.defend` function
#### check.defend(fn, predicates)
function add(a, b) {
return a + b
}
var safeAdd = check.defend(add, check.number, check.number)
add('foo', 2); // 'foo2'
// calling safeAdd('foo', 2) raises an exception
check.raises(safeAdd.bind(null, 'foo', 2)); // true
---
#### protects optional arguments
function add(a, b) {
if (typeof b === 'undefined') {
return 'foo'
}
return a + b
}
add(2); // 'foo'
var safeAdd = check.defend(add, check.number, check.maybe.number)
safeAdd(2, 3); // 5
safeAdd(2); // 'foo'
---
You can add extra message after a predicate
#### check.defend with messages
function add(a, b) {
return a + b
}
var safeAdd = check.defend(add, check.number, 'a should be a number', check.string, 'b should be a string')
safeAdd(2, 'foo'); // '2foo'
function addNumbers() {
return safeAdd(2, 3)
}
function checkException(err) {
err.message; // 'Argument 2: 3 does not pass predicate: b should be a string'
return true
}
check.raises(addNumbers, checkException); // true
---
This works great when combined with JavaScript module pattern as in this example
#### check.defend in module pattern
var add = (function() {
// inner private function without any argument checks
function add(a, b) {
return a + b
}
// return defended function
return check.defend(add, check.number, check.number)
}())
add(2, 3); // 5
// trying to call with non-numbers raises an exception
function callAddWithNonNumbers() {
return add('foo', 'bar')
}
check.raises(callAddWithNonNumbers); // true
---
### Safe callback execution
Sometimes we want to execute a function depending on the condition, but without throwing an
exception. For these cases, there is `check.then`
#### check.then
function isSum10(a, b) {
return a + b === 10
}
function sum(a, b) {
return a + b
}
var onlyAddTo10 = check.then(isSum10, sum)
// isSum10 returns true for these arguments
// then sum is executed
onlyAddTo10(3, 7); // 10
onlyAddTo10(1, 2); // undefined
// sum is never called because isSum10 condition is false
----
#### check.found
Great for quickly checking string or array search results
```js
check.found('foo'.indexOf('f')); // true
check.found('foo bar'.indexOf('bar')); // true
```
#### check.regexp
Returns true if the passed value is a regular expression.
#### check.promise
Returns true if given object has promise methods (`.then`, etc)
#### check.validDate
Returns true if the given instance is a Date and is valid.
#### check.equal
Curried shallow strict comparison
```js
var foo = 'foo';
check.equal(foo, 'foo'); // true
var isFoo = check.equal('foo');
isFoo('foo'); // true
isFoo('bar'); // false
```
#### check.or
Combines multiple predicates into single one using OR logic
```js
var predicate = check.or(check.bool, check.unemptyString);
predicate(true); // true
predicate('foo'); // true
predicate(42); // false
```
It treats non-functions as boolean values
```js
var predicate = check.or(check.unemptyString, 42);
// will always return true
predicate('foo'); // true, because it is unempty string
predicate(false); // true, because 42 is truthy
```
Note: if there are any exceptions inside the individual predicate functions, they are
treated as `false` values.
#### check.and
Combines multiple predicates using AND. If the predicate is not a function,
evaluates it as a boolean value.
```js
function isFoo(x) { return x === 'foo'; }
check.and(check.unemptyString, isFoo); // only true for "foo"
```
Both `check.or` and `check.and` are very useful inside `check.schema` to create
more powerful predicates on the fly.
```js
var isFirstLastNames = check.schema.bind(null, {
first: check.unemptyString,
last: check.unemptyString
});
var isValidPerson = check.schema.bind(null, {
name: check.or(check.unemptyString, isFirstLastNames)
});
isValidPerson({ name: 'foo' }); // true
isValidPerson({ name: {
first: 'foo',
last: 'bar'
}}); // true
```
### Small print
Author: Kensho © 2014
* [@kensho](https://twitter.com/kensho)
* [kensho.com](http://kensho.com)
Support: if you find any problems with this library,
[open issue](https://github.com/kensho-technologies/check-more-types/issues) on Github
This documentation was generated using [grunt-xplain](https://github.com/bahmutov/grunt-xplain)
and [grunt-readme](https://github.com/jonschlinkert/grunt-readme).
## MIT License
The MIT License (MIT)
Copyright (c) 2014 Kensho
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.