no-useless-concat

"a" + "b" is a longer way to write "ab". Two literals next to each other are usually left over after someone removed a variable between them.

Both plain strings and template literals count. Strings on different lines are allowed, because that's a common way to break a long string.

Configure

Off by default. To turn it on:

[lint.rules]
"no-useless-concat" = "error" # or "warn"

Examples

Reported:

const greeting = "Hello, " + "world";
const path = base + "/api" + `/users`;

Not reported:

const greeting = "Hello, world";
const path = base + "/api/users";
const label = "user " + id;

const message = "This sentence is too long for one line, " +
  "so it goes on here.";