What’s New in TypeScript 4.8? Key Changes, Bugs, and Migration Tips

TypeScript 4.8 is currently in the release candidate (RC) stage, with the final stable version expected around August 23.

The team says no major changes are planned beyond critical bug fixes. Since the 4.8 beta, the only notable addition is a new TS server preference that lets you exclude modules or libraries from the auto‑import list used for code completion.

Another change is a stricter check that treats comparisons between objects/arrays and primitive values as errors. For example, the following code now triggers an error because JavaScript compares objects by reference, not by value:

var things: any[] = Array();
if (things == []) {
  // Is the array empty?
}

TypeScript 4.8 reports: “This condition will always return false because JavaScript compares objects by reference rather than by value.”

Google’s internal software team confirmed that a small portion of their libraries needed adjustments to compile with 4.8, but they continue to support the improvements. They advise against using “as any” casts to silence the error, as it can hide potential bugs, even though the impact is limited to about 0.006% of libraries.

Overall, the release aims to catch errors earlier before deployment, making the “correctness fixes” in 4.8 beneficial for developers and projects despite introducing new type errors.