Starbucks (NASDAQ:SBUX) will have a lot to prove next week. The coffee giant is scheduled to report its fiscal third-quarter results on Thursday, July 25. With shares up nearly 40% year to date, investors will be looking for signs that the company's growth story is intact.

Ahead of Starbucks' quarterly update, here's a preview of some of the key areas investors will want to check on.

A woman using Starbucks' mobile loyalty program

Image source: Starbucks.

Revenue

Starbucks has seen its top line grow at a healthy rate recently. Revenue rose 5% year over year in fiscal Q2. But when adjusted for the impact of activities to streamline operations and changes in foreign currencies, revenue increased 9% year over year during the period. This adjusted rate is in line with the company's adjusted revenue growth in the first quarter of fiscal 2019 and an acceleration from 8% adjusted revenue growth for the full year of 2018.

Can Starbucks keep up this accelerated pace of revenue growth?

Comparable-store sales

Starbucks' comparable-store sales, or sales of stores open for 13 months or longer and excluding the effect of changes in foreign currencies, have been rising nicely. In fiscal Q2, comparable sales rose 3% globally, helped by a 4% increase in the U.S. and a 3% rise in China. Further highlighting the company's momentum in comp growth, Starbucks' fiscal second quarter marked its second consecutive quarter of positive transaction growth.

Given management's guidance for global comparable-store sales to rise between 3% to 4% for the full year of fiscal 2019, investors should look for comparable-store sales growth in fiscal Q2 to be near this range.

Rewards members

Another area of strength for Starbucks has been its double-digit growth in U.S.-based Starbucks rewards members. Memberships in the domestic market increased 13% year over year to 16.8 million active members in fiscal Q2. Capturing how important the company's rewards program is, 41% of U.S. sales came from rewards members in Q2, management said in Starbucks' fiscal second-quarter earnings call.

In addition, the company's rewards program in China, which was launched earlier this year, is off to a great start. Since the program's launch, "member acquisition has accelerated and 90-day active rewards members increased by 1 million during Q2 to a total of 8.3 million," said Starbucks CEO Kevin Johnson during the company's most recent earnings call. "The phenomenal growth of the Starbucks rewards program in China is a testament to the power of the brand, we are now building on this momentum with plans to bring mobile order and pay to China by the end of fiscal '19."

Look for more positive updates from management on the company's rewards programs in both the U.S. and China.

Mark your calendar. The coffee giant reports its quarterly results after market close on July 25 and will host a live conference call on the same day at 2 p.m. PDT (5 p.m. EDT).