contextDiff test failure

[unsaved]

Insertion of line at index 19 is totally missed by the comparison:

#!/usr/bin/env node

const difflib = require("difflib");

const origLines =
    ["zero", "one", "two", "three", "four", "five", "six",
     "seven", "eight", "nine", "ten", "eleven",
    "twelve", "thirteen", "fourteen", "fifteen",
    "sixteen", "seventeen", "eighteen", "nineteen"];
const newLines = origLines.slice();
newLines.splice(19, 0, "newteen");
newLines[10] = "changed";
newLines.splice(3, 1);

console.log("Orig: " + origLines);
console.log("New: " + newLines);
console.log(difflib.contextDiff(origLines, newLines,
    { fromfile: "LHS", tofile: "RHS", n: 2, lineterm: "" }
).join("\n"));

[unsaved]

After editing "difflib.js" to pass n to getGroupedOpcodes to work around Issue #8, the contextDiff output now also misses the change of element at index 10 from "nine" to "changed".

#!/usr/bin/env node

const difflib = require("difflib");

const origLines =
    ["zero", "one", "two", "three", "four", "five", "six",
     "seven", "eight", "nine", "ten", "eleven",
    "twelve", "thirteen", "fourteen", "fifteen",
    "sixteen", "seventeen", "eighteen", "nineteen"];
const newLines = origLines.slice();
newLines.splice(19, 0, "newteen");
newLines[10] = "changed";
newLines.splice(3, 1);

console.log("Orig: " + origLines);
console.log("New: " + newLines);
console.log(difflib.contextDiff(origLines, newLines,
    { fromfile: "LHS", tofile: "RHS", n: 2, lineterm: "" }
).join("\n"));