extract custom elements from array with save original array

by Quncore

HTML

<p id="log"></p>

JavaScript

var log = function(item) {
  var p = document.getElementById("log");
  p.innerHTML += item + "<br />"
};
var array = [
  [-0.04, 0.01, 4],
  [-1.09, 9, 0],
  [8.1, 10.4, 7],
  [15, 6, 3]
];
log("original array");
array.forEach(function(item) {
  log("[" + item + "]")
});
var newArray = array.map(function(item){return item.slice()})
log("copy array");
newArray.forEach(function(item) {
  log("[" + item + "]")
});
newArray.forEach(function(item) {
  item.splice(1, 1)
});
log("modified array");
newArray.forEach(function(item) {
  log("[" + item + "]")
});
log("original array");
array.forEach(function(item) {
  log("[" + item + "]")
});