Chinese consumers are starting to "take sides" as the U.S.-China trade dispute rages on, and that could hamper the success of some U.S. companies, CNBC's Jim Cramer said Friday.

Perhaps it already is: U.S. tech giant Apple recently warned that its fiscal first-quarter results would miss expectations due to weaker-than-anticipated iPhone sales in China. Then, earlier on Friday, Goldman Sachs downgraded the stock of Starbucks, citing "a number of points of caution" in the Chinese market.

"We know that the Chinese consumer's beginning to take sides," Cramer said on "Mad Money." "That's not good news for any American companies that do business over there, even if many of their stocks seem to reflect that we might be getting some progress in the trade talks."

Cramer was referring to shares of apparel companies like Nike, Lululemon and Tapestry, all of which do business in China but have not seen their sales slow in a material way. Stocks of industrials with ties to the People's Republic, like Boeing and Deere, an agricultural play that should be suffering from tariffs on U.S. crops, are also holding firm.

"I wonder if the action in Deere is signaling that maybe we'll get some progress in these Chinese trade talks, or, at the very least, they'll make a bunch of ag[ricultural] purchases as a show of good faith," the "Mad Money" host wondered.

But the best ways to gauge trade talk progress in Cramer's book are what he called "the three As": American Express, Apple and aerospace.

If American Express is able to get a license to operate in China, that will signal that China is ready to embrace the U.S. financial sector, Cramer explained. If the Chinese government "starts making nice" with Apple, that would also be "very positive," he said, much better than the news of iPhone price slashes in China that made waves Friday.

"But the most important show of good faith would be for China Airlines to place a gigantic order of planes with Boeing, an order that would reverberate throughout the entire aerospace complex, including Honeywell, United Technologies, and GE, ... which is finally starting to [trade] like an aerospace and industrial stock again," Cramer said.

For now, though, the "winners and losers in China" are starting to emerge, and there's no denying that "the Chinese economy's gotten pretty tricky here, especially for American companies," he said.

"Frankly, China's become unfathomable at the moment. We have no idea [what] their government's doing, what it's thinking," Cramer said. "Maybe it's darkest before the dawn, but I'd argue it's ill-advised to predict the dawn until we're further along into the night."

Stocks sank in Friday's trading session as worries about an economic slowdown in China took hold. For a timeline of the trade war and tariff exchanges between U.S. and Chinese trade authorities, click here.