function get() {
	/* eslint-disable no-invalid-this */
	var min;
	var len;
	var d;
	var i;

	if ( this._yMin === null ) {
		len = this._data.length;
		min = PINF;
		for ( i = 0; i < len; i++ ) {
			d = this._data[ i ];
			if ( this._isDefined( d ) && d !== NINF && d < min ) {
				min = d;
			}
		}
		return min;
	}
	return this._yMin;
}
Returns the minimum value of the y-axis domain.

@private
@returns {number} minimum value of the y-axis domain