Synopsis

pred is a library of JavaScript predicates (functions that test their input and return a boolean).

Install

With NPM

npm install pred

From source

git clone https://github.com/pluma/pred.git
cd pred
npm install
make test

API

Complex predicates

all(predicates…):Function

Returns a predicate that returns true if all of the predicates return true for the given input.

any(predicates…):Function

Returns a predicate that returns true if any of the predicates return true for the given input.

equals(value):Function

Returns a predicate that returns true if the input is identical to the given value (using === strict equal comparison).

deepEquals(value):Function

Returns a predicate that returns true if the input is equivalent to the given value.

Example:

console.log(deepEquals({a: {b: ['c']}})({a: {b: ['c']}})); // true

greaterThan(value:Number):Function

Returns a predicate that returns true if the input is greater than (but not equal to) the given value.

lessThan(value:Number):Function

Returns a predicate that returns true if the input is less than (but not equal to) the given value.

inRange(minValue:Number, maxValue:Number):Function

Returns a predicate that returns true if the input is greater than (or equal to) the given minValue but less than (but not equal to) the given maxValue.

hasProperty(name:String):Function

Returns a predicate that returns true if the input is an object that has a property with the given name.

hasProperties(names:Array):Function

Returns a predicate that returns true if the input is an object that has a property with each of the given names.

hasProperties(properties:Object):Function

Returns a predicate that returns true if the input is an object that has a property matching the given properties (name/value mapping).

matches(re:RegExp):Function

Returns a predicate that returns true if the input value matches the given regular expression.

isInstance(Constructor:Function):Function

Returns a predicate that returns true if the input value is an instance of the given constructor function.

isPrototypeOf(object):Function

Returns a predicate that returns true if the input value is the prototype of the given object.

hasPrototype(proto):Function

Returns a predicate that returns true if the given prototype is the prototype of the input value.

Simple predicates

falsey(value):Boolean

Returns true if the input is falsey (i.e. evaluates as boolean false).

truthy(value):Boolean

Returns true if the input is truthy (i.e. evaluates as boolean true).

allEqual(value):Boolean

Returns true if the input is array-like and all of its items are equal, or if it is not array-like.

isArray(value):Boolean

Returns true if the given value is an Array.

isArrayLike(value):Boolean

Returns true if the given value is an Array or an object with a numeric length property.

isBoolean(value):Boolean

Returns true if the given value is a Boolean.

isEmpty(value):Boolean

Returns true if the given value is falsey, an array-like object with length zero or an object with no properties.

isFunction(value):Boolean

Returns true if the given value is a Function.

isNaN(value):Boolean

Returns true if the given value is NaN.

isNull(value):Boolean

Returns true if the given value is null.

isNumber(value):Boolean

Returns true if the given value is a number other than NaN.

isObject(value):Boolean

Returns true if the given value is an object other than null.

isPlainObject(value):Boolean

Returns true if the given value is an instance of Object.

isString(value):Boolean

Returns true if the given value is a string.

isUndefined(value):Boolean

Returns true if the given value is undefined.

Unlicense

This is free and unencumbered public domain software. For more information, see http://unlicense.org/ or the accompanying UNLICENSE file.