vinyl-iscustomprop.md

Vinyl.isCustomProp()

Determines if a property is internally managed by Vinyl. Used by Vinyl when setting values inside the constructor or when copying properties in the clone() instance method.

This method is useful when extending the Vinyl class. Detailed in Extending Vinyl below.

Usage

const Vinyl = require('vinyl');

Vinyl.isCustomProp('sourceMap') === true;
Vinyl.isCustomProp('path') === false;

Signature

Vinyl.isCustomProp(property)

Parameters

parameter	type	note
property	string	The property name to check.

Returns

True if the property is not internally managed.

Extending Vinyl

When custom properties are managed internally, the static isCustomProp method must be extended and return false when one of the custom properties is queried.

const Vinyl = require('vinyl');

const builtInProps = ['foo', '_foo'];

class SuperFile extends Vinyl {
  constructor(options) {
    super(options);
    this._foo = 'example internal read-only value';
  }

  get foo() {
    return this._foo;
  }

  static isCustomProp(name) {
    return super.isCustomProp(name) && builtInProps.indexOf(name) === -1;
  }
}

In the example above, foo and _foo will not be assigned to the new object when cloning or passed in options to new SuperFile(options).

If your custom properties or logic require special handling during cloning, override the clone method while extending Vinyl.