[Javascript] Chaining the Array map and filter methods

Both map and filter do not modify the array. Instead they return a new array of the results. Because both map and filter return Arrays, we can chain these functions together to build complex array transformations with very little code. Finally we can consume the newly created array using forEach. In this lesson, we will learn how to build nontrivial programs without using any loops at all.

var stocks = [
  { symbol: "XFX", price: 240.22, volume: 23432 },
  { symbol: "TNZ", price: 332.19, volume: 234 },
  { symbol: "JXJ", price: 120.22, volume: 5323 },
];

var filteredStockSymbols = 
  stocks.
    filter(function(stock) {
      return stock.price >= 150.00;
    }).
    map(function(stock) {
      return stock.symbol;
    })

filteredStockSymbols.forEach(function(symbol) {
  console.log(symbol);
})