Assigns default values to an object along with validating for required and unknown property keys.

npm i default-options --save

var dopts = require('default-options');

dopts(options, defaults, [doptsOptions]);

• options - The user specified options object
• defaults - An object of defaults for values not specified in options. If a default property value is set specifically to undefined, it will be treated as a required property.
• doptsOptions - Optional object of options for the dopts function.
  • doptsOptions.allowUnknown If set to true, will not throw an error if an unknown property is specified. (default is false)
• Returns defaults merged with options

Example:

var dopts = require('default-options');

dopts({foo: 1, bar: 1}, {
  foo: undefined, // undefined means required
  bar: 2,         // optional
  baz: null,      // optional
});
// Returns {foo: 1, bar: 1, baz: null}

dopts({foo:1}, {
  foo: undefined,
  bar: undefined
});
// Throws an Error because `bar` is not defined

dopts({foo: 1, biz: 2}, {
  foo: undefined
});
// Throws an Error because `biz` is an unknown property