CoffeeScript checks whether the type of variable is an array

Check if the type of variable is an array

Problem

You want to check if a variable is an array.

myArray = []
console.log typeof myArray // outputs 'object'

The "typeof" operator outputs an incorrect result for the array.

Solution

Use the following code:

typeIsArray = Array.isArray || ( value ) -> return {}.toString.call( value ) is '[object Array]'

To use this, call type IsArray like this.

myArray = []
typeIsArray myArray // outputs true

Discuss

The above method is taken from "The Miller Device". Another way is to use Dougglas Crockford's fragments.

typeIsArray = ( value ) ->
    value and
        typeof value is 'object' and
        value instanceof Array and
        typeof value.length is 'number' and
        typeof value.splice is 'function' and
        not ( value.propertyIsEnumerable 'length' )