{
  // A string of more lines than the limit renders as an excerpt of that many
  // lines, line breaks included, and then its actual length.
  "/options": { maxStringLines: 2 },

  "past the limit": "a\nb\nc\nd",
  "at the limit": "a\nb",
  "in an object": { s: "a\nb\nc" },

  // A line break is a newline, a carriage return, or the two together.
  "carriage returns": "a\r\nb\rc\nd",

  // A line break at the end of the string ends its last line rather than
  // starting another.
  "ending in a line break, at the limit": "a\nb\n",
  "ending in an empty line, past the limit": "a\nb\n\n",

  // A line cut keeps a lone high surrogate ahead of the line break, where a
  // length cut would drop it.
  "high surrogate before the break": "a\nb\ud800\nc",

  // The length limit is not applied when only the line limit is given.
  "210 characters on one line": "x".repeat(210),
}

--

past the limit:
"a\nb\n"+...length:7
"a\n" +
  "b\n" +
  ... length: 7
{
  "/partialString": {
    length: 7,
    excerpt: "a\n" +
      "b\n"
  }
}

at the limit:
"a\nb"
"a\n" +
  "b"
"a\n" +
  "b"

in an object:
{s:"a\nb\n"+...length:5}
{
  s: "a\n" +
    "b\n" +
    ... length: 5
}
{
  s: {
    "/partialString": {
      length: 5,
      excerpt: "a\n" +
        "b\n"
    }
  }
}

carriage returns:
"a\r\nb\r"+...length:8
"a\r\n" +
  "b\r" +
  ... length: 8
{
  "/partialString": {
    length: 8,
    excerpt: "a\r\n" +
      "b\r"
  }
}

ending in a line break, at the limit:
"a\nb\n"
"a\n" +
  "b\n"
"a\n" +
  "b\n"

ending in an empty line, past the limit:
"a\nb\n"+...length:5
"a\n" +
  "b\n" +
  ... length: 5
{
  "/partialString": {
    length: 5,
    excerpt: "a\n" +
      "b\n"
  }
}

high surrogate before the break:
"a\nb\ud800\n"+...length:6
"a\n" +
  "b\ud800\n" +
  ... length: 6
{
  "/partialString": {
    length: 6,
    excerpt: "a\n" +
      "b\ud800\n"
  }
}

210 characters on one line:
"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"