Purescript binary tree codegen

Tree.purs

module Main where

import Prelude

data Tree a = Empty | Leaf a | Node a (Tree a) (Tree a)

depthFirstTraversal x =
  case x of
    Empty -> []
    Leaf a -> [a]
    Node a left right -> depthFirstTraversal left <> [a] <> depthFirstTraversal right

Tree.purs.js

"use strict";
var Data_Semigroup = require("../Data.Semigroup");
var Prelude = require("../Prelude");
var Empty = (function () {
    function Empty() {

    };
    Empty.value = new Empty();
    return Empty;
})();
var Leaf = (function () {
    function Leaf(value0) {
        this.value0 = value0;
    };
    Leaf.create = function (value0) {
        return new Leaf(value0);
    };
    return Leaf;
})();
var Node = (function () {
    function Node(value0, value1, value2) {
        this.value0 = value0;
        this.value1 = value1;
        this.value2 = value2;
    };
    Node.create = function (value0) {
        return function (value1) {
            return function (value2) {
                return new Node(value0, value1, value2);
            };
        };
    };
    return Node;
})();
var depthFirstTraversal = function (x) {
    if (x instanceof Empty) {
        return [  ];
    };
    if (x instanceof Leaf) {
        return [ x.value0 ];
    };
    if (x instanceof Node) {
        return Data_Semigroup.append(Data_Semigroup.semigroupArray)(depthFirstTraversal(x.value1))(Data_Semigroup.append(Data_Semigroup.semigroupArray)([ x.value0 ])(depthFirstTraversal(x.value2)));
    };
    throw new Error("Failed pattern match at Main line 8, column 3 - line 11, column 81: " + [ x.constructor.name ]);
};
module.exports = {
    Empty: Empty, 
    Leaf: Leaf, 
    Node: Node, 
    depthFirstTraversal: depthFirstTraversal
};