@kingjs/descriptor.filter

Filters and renames properties.

Usage

Create a new descriptor and the copy values in properties $alpha, $bravo, and $delta from an existing descriptor into properties with names alpha, bravo, and delta like this:

var filter = require('@kingjs/descriptor.filter');

filter.call({
  $alpha: 0,
  $bravo: 1,
  $delta: 2,
  value: 3
}, {
  $alpha: 'alpha',
  $bravo: 'bravo',
  $delta: 'delta'
});

result:

{
  alpha: 0,
  bravo: 1,
  delta: 2
}

The same result can also be achieved procedurally like this:

var filter = require('@kingjs/descriptor.filter');

filter.call({
  $alpha: 0,
  $bravo: 1,
  $delta: 2,
  value: 3
}, function(name) {
  if (name == 'value')
    return undefined;
  
  return name.substr(1);
});

result:

{
  alpha: 0,
  bravo: 1,
  delta: 2
}

API

declare function filter(
  this: Descriptor,
  source: Descriptor,
  map: { 
    [index: string]: string | number, 
    [index: number]: string | number 
  } | { 
    (name: string): string | number
  },
  thisArgs?
): Descriptor

Interfaces

• Descriptor: see @kingjs/descriptor

Parameters

• this: The descriptor whose renamed properties will be copied to a new descriptor.
• map: Either
  • A descriptor containing a mapping of property names on this to names on the new descriptor. Properties on this not included in map will not be copied.
  • A callback which maps names on this to names on the new descriptor. If the callback returns undefined then the property value is not copied.
• thisArg: The this argument to pass to map should map be a function.

Returns

A new descriptor with a copy of a subset of properties from this but with different property names according to map or null if no properties were copied.

Remarks

No check is made to ensure mapped names are unique. Behavior is undefined when if duplicate names are provided.

Install

With npm installed, run

$ npm install @kingjs/descriptor.filter

License

MIT