Function nullish

test/test-spec-tests.js:57–62

(nullOrString)

// The source-map library converts null sources to the "null" URL in its
// sources list, so for equality checking we accept this as null.
function nullish(nullOrString) {
  if (nullOrString === "null") {
    return null;
  }
  return nullOrString;
}

function mapLine(line) {
  return line + 1;