default-val

default-value

Set default value with type check.

Install

$ npm i default-val --save

Usage

• Load this mudule :

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

• Get default value if the property is undefined or null :

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

• Get default property value if the number property is NaN :

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

• Get default property value if the type of the property 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 get value if it is invalid :

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

API

defaultValue(value, defaultValue [, 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.
  • defaultValue [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 defaultValue.

License

Copyright (C) 2017 Takayuki Sato

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