Eslint: Is there a way to get warning about multiline concatenation?

[vsemozhetbyt]

Tell us about your environment

• ESLint Version: 3.13.0
• Node Version: 7.4.0
• npm Version: 4.0.5

What parser (default, Babel-ESLint, etc.) are you using?
default

Please show your configuration:

no-useless-concat: "error",
prefer-template: "error",

What did you do? Please include the actual source code causing the issue.

Let's assume I have a legacy code:

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

What did you expect to happen?
A message proposing multiline template string, so I could replace it by:

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

What actually happened? Please include the actual, raw output from ESLint.
No reports.

[platinumazure]

I'd say no-useless-concat would be the rule where this should happen, but it looks like it intentionally allows useless concatenation when it's multi-line.

I would be open to seeing a new option in that rule which would report even multi-line strings. Maybe an object option like { "reportMultiLineStrings": true } or something like that. If that enhancement seems reasonable to you, would you mind filling out the rule change proposal template? Then we can evaluate the proposal :smile:

[vsemozhetbyt]

@platinumazure Done.

[platinumazure]

Thanks! I'm going to go ahead and close this issue since it's been superseded by the new one.