function set( color ) {
	/* eslint-disable no-invalid-this */
	if ( !isString( color ) ) {
		throw new TypeError( format( 'invalid assignment. `%s` must be a string. Value: `%s`.', 'color', color ) );
	}
	debug( 'Current value: %d.', this._color );

	this._color = color;
	debug( 'New Value: %d.', this._color );

	this.emit( 'change' );
}
Sets the path color.

@private
@param {string} color - color
@throws {TypeError} must be a string