calculateAdjacent hash method fails when hash borders longitude or latitude limits about geohash-js HOT 2 OPEN

 public static String adjacentHash(String hash, Direction direction) {
        checkHash(hash);
        Preconditions
                .checkArgument(hash.length() > 0,
                        "adjacent has no meaning for a zero length hash that covers the whole world");

        // check if hash is on edge and direction would push us over the edge
        // if so, wrap round to the other limit for longitude
        // or if at latitude boundary (a pole) then spin longitude around 180
        // degrees.
        LatLong centre = decodeHash(hash);

        // if rightmost hash
        if (Direction.RIGHT.equals(direction)
                && Math.abs(centre.getLon() + widthDegrees(hash.length()) / 2
                        - 180) < PRECISION) {
            return encodeHash(centre.getLat(), -180, hash.length());
        }
        // if leftmost hash
        if (Direction.LEFT.equals(direction)
                && Math.abs(centre.getLon() - widthDegrees(hash.length()) / 2
                        + 180) < PRECISION) {
            return encodeHash(centre.getLat(), 180, hash.length());
        }
        // if topmost hash
        if (Direction.TOP.equals(direction)
                && Math.abs(centre.getLat() + widthDegrees(hash.length()) / 2
                        - 90) < PRECISION) {
            return encodeHash(centre.getLat(), centre.getLon() + 180,
                    hash.length());
        }
        // if bottommost hash
        if (Direction.BOTTOM.equals(direction)
                && Math.abs(centre.getLat() - widthDegrees(hash.length()) / 2
                        + 90) < PRECISION) {
            return encodeHash(centre.getLat(), centre.getLon() + 180,
                    hash.length());
        }

        String source = hash.toLowerCase();
        char lastChar = source.charAt(source.length() - 1);
        Parity parity = (source.length() % 2 == 0) ? Parity.EVEN : Parity.ODD;
        String base = source.substring(0, source.length() - 1);
        if (BORDERS.get(direction).get(parity).indexOf(lastChar) != -1)
            base = adjacentHash(base, direction);
        return base
                + BASE32.charAt(NEIGHBOURS.get(direction).get(parity)
                        .indexOf(lastChar));
    }