Employers that want to keep their developers happy should make sure they’re clear about the details and requirements of a position. HackerRank released its 2019 Developer Skills Report, which found 68 percent of developers say nothing irks them more than being unsure of what is expected of them.

“Hiring and retaining skilled developers is critical for businesses everywhere. Recruiters and hiring managers need a deep understanding of who developers are, what they care about and what they want from their employers. For example, nearly half of developers view values misalignment as a deal-breaker when considering a job opportunity,” said Vivek Ravisankar, co-founder and CEO of HackerRank. “We want to match every developer to the right job, and this data gives engineering teams a blueprint to find and keep the best developers for their roles.”

The report is based on the responses of more than 71,000 software developers from more than 100 countries.

As far as what makes employees optimistic about a position, professional growth and learning was key for about 65 percent of developers, and work-life balance for about 46 percent. But in addition to a lack of clarity, 49 percent of developers said a lack of aligned values and 14 percent of developers said a lack of diversity both increased unhappiness with a position or workplace.

The issue of diversity is hardly helped, the survey found, by the United States’ recent tighter immigration policies. HackerRank explained that a third of hiring managers reported U.S. immigration policies as a detriment to their ability to find suitable talent. These same policies, the report found, are discouraging to developers outside of the United States, with 27 percent of them responding that they or someone they know have been put off by the tighter restrictions.

But developers concerned with their workplaces were very likely to raise those concerns, with 38 percent of respondents saying that they spoke up. The following 23 percent just up and quit their positions.

The number one concern once a developer has been hired and begun working, the survey found, was messy code, with 65 percent of respondents ranking it at the top, followed by poorly written documentation, ranked at the top spot by 57 percent of respondents.

The survey also looked at the programming languages being used by developers, and found JavaScript was the most used programming language of 2018, surpassing last years’ most-used language, Java, with over 60 percent of respondents saying that they knew JavaScript. In addition, the report found that React will likely overtake AngularJS as the most popular JavaScript framework in 2019, with a jump in knowledge from 20 percent to 26 percent of respondents.

Other technologies that are on the rise include IoT, with 53 percent of respondents predicting it will be adopted most in the near future, and deep learning following closely behind at 50 percent. On the other hand cryptocurrency and blockchain was considered “unpredictable” by respondents, with around 20 percent of the developers calling the technology’s growth over the next two years “overhyped.”

The survey also noted a generational divide marked by what sorts of projects developers considered their first programming project, as well as what sorts of music they listen to while coding. For millennial and Gen Z respondents, calculators and simple websites gave them their start (while they bopped to electronic music and hip-hop according to the survey), while a majority of Gen X and Baby Boomer respondents started with a game (while enjoying electronic and classical music, and classical and rock music, respectively).

The full report is available here.