Proposal for no-useless-concat to report multiline strings

What rule do you want to change? no-useless-concat

Does this change cause the rule to produce more or fewer warnings? More.

How will the change be implemented? (New option, new default behavior, etc.)? An object option like { "reportMultiLineStrings": true }.

Please provide some example code that this change will affect:

const privateKey =
'-----BEGIN EC PRIVATE KEY-----\n' +
'MHcCAQEEIF+jnWY1D5kbVYDNvxxo/Y+ku2uJPDwS0r/VuPZQrjjVoAoGCCqGSM49\n' +
'AwEHoUQDQgAEurOxfSxmqIRYzJVagdZfMMSjRNNhB8i3mXyIMq704m2m52FdfKZ2\n' +
'pQhByd5eyj3lgZ7m7jbchtdgyOF8Io/1ng==\n' +
'-----END EC PRIVATE KEY-----\n';

What does the rule currently do for this code? No warning.

What will the rule do after it’s changed? Propose multiline template literal.

See also this comment.

[jhitchins88]

Basically you want…

const privateKey =
'-----BEGIN EC PRIVATE KEY-----\n' +
'MHcCAQEEIF+jnWY1D5kbVYDNvxxo/Y+ku2uJPDwS0r/VuPZQrjjVoAoGCCqGSM49\n' +
'AwEHoUQDQgAEurOxfSxmqIRYzJVagdZfMMSjRNNhB8i3mXyIMq704m2m52FdfKZ2\n' +
'pQhByd5eyj3lgZ7m7jbchtdgyOF8Io/1ng==\n' +
'-----END EC PRIVATE KEY-----\n';

…to be written like…

const privateKey =
`-----BEGIN EC PRIVATE KEY-----
MHcCAQEEIF+jnWY1D5kbVYDNvxxo/Y+ku2uJPDwS0r/VuPZQrjjVoAoGCCqGSM49
'AwEHoUQDQgAEurOxfSxmqIRYzJVagdZfMMSjRNNhB8i3mXyIMq704m2m52FdfKZ2
'pQhByd5eyj3lgZ7m7jbchtdgyOF8Io/1ng==
'-----END EC PRIVATE KEY-----\n`;

The rule would be okay with this, correct?

const fileName = "/test/test/test/test/testDir/reallyLongDirName" +
    "/it/just/keeps/on/going"

It would search for two strings being concatenated on a line break with a new line character. I’m for it. I’d also be down for implementing it. It shouldn’t be a terribly difficult rule to apply.

[not-an-aardvark]

Thanks for your interest in improving ESLint. Unfortunately, it looks like this issue didn’t get enough support from the team and so I’m closing it. While we wish we’d be able to accommodate everyone’s requests, we do need to prioritize. We’ve found that issues failing to reach consensus after a long time tend to never do it, and as such, we close those issues. This doesn’t mean the idea isn’t interesting, just that it’s not something the team can commit to.