1) Converting to boolean using !! operator
function Account(cash) {
this.cash = cash;
this.hasMoney = !!cash;
}
2) Converting to number using + operator
function toNumber(strNumber) {
return +strNumber;
}
console.log(toNumber("1234")); // 1234
console.log(toNumber("ACB")); // NaN
3) Short-circuits conditionals
user && user.login();
| 4) Default values using | operator |
this.name = name || "Oliver Queen";
5) Caching the array.length in the loop
for(var i = 0, length = array.length; i < length; i++) {
console.log(array[i]);
}
6) Detecting properties in an object
if ('querySelector' in document) {
document.querySelector("#id");
} else {
document.getElementById("id");
}
7) Getting the last item in the array
var array = [1,2,3,4,5,6];
console.log(array.slice(-1)); // [6]
console.log(array.slice(-2)); // [5,6]
console.log(array.slice(-3)); // [4,5,6]
8) Array truncation
var array = [1,2,3,4,5,6];
console.log(array.length); // 6
array.length = 3;
console.log(array.length); // 3
console.log(array); // [1,2,3]
9) Replace all
/g
string.replace(/hn/g, "ana"))
10) Merging arrays
Array.concat()
11) Converting NodeList to Arrays
[].slice.call(elements) / Array.from(elements)
var elements = document.querySelectorAll("p"); // NodeList
var arrayElements = [].slice.call(elements); // Now the NodeList is an array
var arrayElements = Array.from(elements); // This is another way of converting NodeList to Array
12) Shuffling array’s elements
var list = [1,2,3];
console.log(list.sort(function() { Math.random() - 0.5 })); // [2,1,3]