includes method

forEach method

Do do something with each item of the array

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function getStockSymbols(stocks) {
  var symbols = [];

  stocks.forEach(function(stock) {
    symbols.push(stock.symbol);
  });

  return symbols;
}

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

console.log(JSON.stringify(symbols));

map method

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function getStockSymbols(stocks) {
  return stocks.map((stock) => stock.symbol);
}

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

console.log(JSON.stringify(symbols));

filter method

create a new array containing only those items the passed the test.

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function getStocksOver(stocks, minPrice) {
  return stocks.filter((stock)  => stock.price >= minPrice);
}

var expensiveStocks = getStocksOver([
  { symbol: "XFX", price: 240.22, volume: 23432 },
  { symbol: "TNZ", price: 332.19, volume: 234 },
  { symbol: "JXJ", price: 120.22, volume: 5323 },
],
150.00);

console.log(JSON.stringify(expensiveStocks));

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

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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;
    })

Initialize an Array with Values

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var itemArray = new Array('item 1', 'item 2', 'items 3');
var itamArrayLit = ['item 1', 'item 2', 'item 3'];

Créer un un tableau de taille précise et le remplir avec des objets

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Array.from({length: nb}, () => new StyledContainer()); // Créer une nouvelle instance pour chaque item du tableau
new Array(9).fill(0); // Va remplir le tableau de 9 0, par coutre si c'est un objet, il va remplir le tableau 9 fois avec la même instance de l'objet. (donc si on supprime une instance dans le tableau, le tableau va etre vide)

ex http://jsbin.com/zusezinutu/1/edit?js,console

Convert an Array to a String

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var numberArray = [1, 2, 3, 4, 5, 5, 6, 7, 8, 9];  // returns [1, 2, 3, 4, 5, 5, 6, 7, 8, 9]
console.log( numberArray.toString() ); //returns 1,2,3,4,5,6,7,8,9
console.log( numberArray.join('') );  //returns 123456789

Add Items to an Array Within a Range

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var numberArray = [1,2,3,4];
numberArray.fill(5, 0, 1);
console.log(numberArray); //result [5, 2, 3, 4]

The Fill Method Will Add a Value Based on the Start and Ending Index Numbers

Append an Array to the End of Another Array

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var numberArray = [1,2,3,4];
var numberArray2 = [5,6,7,8];
var resultArray = numberArray.concat(numberArray2);

Reverse the Order of the Items in an Array

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var numberArray = [1, 2, 3, 4, 5, 6, 7, 8, 9];
    numberArray.reverse();
console.log(numberArray);  //returns [9,8,7,6,5,4,3,2,1]