Equivalent of set in ES6 to ES5

Question

I have a set over which I am iterating in ES6. I am trying to convert it to its equivalent in ES5. My build is getting failed because of ES6. That\'s why I am converting it

Answer 1

Why not just iterate through the data and map the result with Array#map.

result = deviceList.map(function (item) {
    return { deviceName: item };
});

Answer 2

I think your problem with your second for example is just that length is a property and not a function so you shouldn't add () to the end of it. A working version of this might look like this:

for(var i = 0; i < deviceList.length; i++){
  result.push({"deviceName" : deviceList[i]});
}

This assumes (as @grabantot pointed out) that deviceList is an array, however, if it's a Set then you need to use the deviceList.size property.

However, there is a more compatible version of your first for loop which is the forEach() function (which is available on Array and Set), like this:

deviceList.forEach(function (item) {
  result.push({"deviceName": item});
});

Answer 3

This is a basic set es5 class that I have used variations on over the years.

function Set(items) {
  this._data = {};
  this.addItems(items);
}

Set.prototype.addItem = function(value) {
  this._data[value] = true;
  return this;
}

Set.prototype.removeItem = function(value) {
  delete this._data[value];
  return this;
}

Set.prototype.addItems = function(values) {
  for (var i = 0; i < values.length; i++) {
    this.addItem(values[i]);
  }
  return this;
}

Set.prototype.removeItems = function(values) {
  for (var i = 0; i < values.length; i++) {
    this.removeItem(values[i]);
  }
  return this;
}

Set.prototype.contains = function(value) {
  return !!this._data[value];
}

Set.prototype.reset = function() {
  this._data = {};
  return this;
}

Set.prototype.data = function() {
  return Object.keys(this._data);
}

Set.prototype.each = function(callback) {
  var data = this.data();
  for (var i = 0; i < data.length; i++) {
    callback(data[i]);
  }
}

var set = new Set(['a', 'b', 'c']);
console.log(set.addItems(['a', 'd', 'e']).removeItems(['b', 'e']).data());
console.log(set.contains('a'));
console.log(set.contains('e'));

set.each(console.log)