Chai@4.4.0 syntax error in assertion.js:69

[breandandalton]

Environment:
We are currently picking up chai@4.4.0 in our dependency "chai": "^4.1.1".
Resolved dependencies:
+-- chai@4.4.0
| +-- assertion-error@1.1.0
| +-- check-error@1.0.3
| +-- deep-eql@4.1.3
| +-- get-func-name@2.0.2
| +-- loupe@2.3.7
| +-- pathval@1.1.1
| `-- type-detect@4.0.8

Problem
First noticed this problem during a nightly build, at 2024-01-07T00:28:35.648Z (shortly after 4.4.0 was last published) and nightly thereafter:

[2024-01-07T00:28:35.648Z] /srv/mantle-cucumber/node_modules/chai/lib/chai/assertion.js:69
[2024-01-07T00:28:35.648Z] flag(this, 'eql', config.deepEqual ?? util.eql);
[2024-01-07T00:28:35.648Z] ^
[2024-01-07T00:28:35.648Z]
[2024-01-07T00:28:35.648Z] SyntaxError: Unexpected token ?
[2024-01-07T00:28:35.648Z] at createScript (vm.js:56:10)
[2024-01-07T00:28:35.648Z] at Object.runInThisContext (vm.js:97:10)
[2024-01-07T00:28:35.648Z] at Module._compile (module.js:549:28)
[2024-01-07T00:28:35.648Z] at Object.Module._extensions..js (module.js:586:10)
[2024-01-07T00:28:35.648Z] at Module.load (module.js:494:32)
[2024-01-07T00:28:35.648Z] at tryModuleLoad (module.js:453:12)
[2024-01-07T00:28:35.648Z] at Function.Module._load (module.js:445:3)
[2024-01-07T00:28:35.648Z] at Module.require (module.js:504:17)
[2024-01-07T00:28:35.648Z] at require (internal/module.js:20:19)
[2024-01-07T00:28:35.648Z] at Object. (/srv/mantle-cucumber/node_modules/chai/lib/chai.js:63:17)

Reverting to version 4.3.10 resolved the issue.

[43081j]

seems this is because a PR introduced ?? syntax which breaks node compatibility

what version of node do you use?

you can prove that's the case by using a newer node version temporarily and seeing if the error stops happening.

if that is the case, we may need to revert the syntax

[koddsson]

Fixed in 4.4.1.