default-val

default-value

Get a default value when a value is nullish or invalid type

Install

$ npm i default-val --save

Usage

• Load this mudule :

  const defaultValue = require('default-val');
  

• Return the default value when the value is undefined or null :

  defaultValue(undefined, true) // => true
  defaultValue(null, 123) // => 123
  

• Return the default value when the value is NaN :

  defaultValue(NaN, 123) // => 123
  defaultValue(Infinity, 123) // => Infinity
  

• Return the default value when the type of the value is invalid :

  defaultValue(987, true) // => true
  defaultValue(987, 'ABC', 'string') // => 'ABC'
  defaultValue(987, 'ABC', '[object String]') // => 'ABC'
  defaultValue(987, 123, '[object String]') // => 123
  defaultValue(987, new Date(0), '[object Date]') // => new Date(0)
  

• And return the value when it is valid :

  defaultValue(987, 0) // => 987
  defaultValue(987, 123, 'number') // => 987
  defaultValue(987, null, 'number') // => 987
  defaultValue(987, 'ABC', '[object Number]') // => 987
  

API

defaultValue(value, defValue [, type]) => any

Returns the second argument when the first argument is null, undefined or NaN, or the type of the first argument is different from the type of the second argument. When the third argument is specified, returns the second argument if the type of the first argument is different from the type represented by the third argument. The third argument can be specified the result of typeof x or Object.prototype.toString.call(x).

• Arguments:

  • value [any] : a value to be evaluated.
  • defValue [any] : a default value which is returned if value is invalid.
  • type [string] : a type for a valid value. (optional)

• Return [any] : value if value is valid, otherwise defValue.

License

Copyright (C) 2017 Takayuki Sato

This program is free software under MIT License. See the file LICENSE in this distribution for more details.