function set( width ) {
	/* eslint-disable no-invalid-this */
	if ( !isPositiveNumber( width ) ) {
		throw new TypeError( format( 'invalid assignment. `%s` must be a positive number. Value: `%s`.', 'width', width ) );
	}
	if ( width !== this._width ) {
		debug( 'Current value: %d.', this._width );

		this._width = width;
		debug( 'New value: %d.', this._width );

		this.emit( 'change' );
	}
}
Sets the width.

@private
@param {PositiveNumber} width - width
@throws {TypeError} must be a positive number