Page 113 - JavaScript

clone3 = [...arrayToClone] // the shortest way

5.1

arrayToClone = [1, 2, 3, 4, 5];
clone1 = Array.prototype.slice.call(arrayToClone);
clone2 = [].slice.call(arrayToClone);

Searching an Array

The recommended way (Since ES5) is to use Array.prototype.find:

let people = [
{ name: "bob" },
{ name: "john" }
];

let bob = people.find(person => person.name === "bob");

// Or, more verbose
let bob = people.find(function(person) {
return person.name === "bob";
});

In any version of JavaScript, a standard for loop can be used as well:

for (var i = 0; i < people.length; i++) {
if (people[i].name === "bob") {
break; // we found bob
}
}

FindIndex

The findIndex() method returns an index in the array, if an element in the array satisfies the
provided testing function. Otherwise -1 is returned.

array = [
{ value: 1 },
{ value: 2 },
{ value: 3 },
{ value: 4 },
{ value: 5 }
];
var index = array.findIndex(item => item.value === 3); // 2
var index = array.findIndex(item => item.value === 12); // -1

Removing/Adding elements using splice()

The splice()method can be used to remove elements from an array. In this example, we remove
the first 3 from the array.

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