Function callback

test/diff/line.js:73–76

(diffResult)

      });
      it('terminates early - async', function(done) {
        function callback(diffResult) {
          expect(diffResult).to.be.undefined;
          done();
        }
        diffLines(
          'line\nold value\nline',
          'line\nnew value\nline', { callback, maxEditLength: 1 });