[Solved] What does [ ] mean in JS?

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Introduction

The square brackets [ ] are a fundamental part of the JavaScript language. They are used to denote an array, an object, or a function argument. They can also be used to access elements of an array or object, or to call a function with an argument. In this article, we will discuss what the square brackets mean in JavaScript and how they are used.

Solution

In JavaScript, [ ] is used to denote an array. An array is a data structure that stores a collection of elements. Each element can be accessed by its index, which is a numerical value that corresponds to the position of the element in the array.


[] is used in arrays to specify the index we need to access, when we say:

someArray[0] we are getting the value from array’s first index and in your case it is

specifying the index via variable which is coming from the loop and in second it is

specifying object’s property to get the property value from that index which is passed in 1st []:

dateList[i]["name"]

in this case it will return you the ith index element of array’s name property value.

if you say dateList[0]["name"] it will reutrn “Mike Jenson” because it is the value

of first array object’s name property value.

An alterantive is dateList[0].name this will also return the same result.

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solved What does [ ] mean in JS?


The square brackets in JavaScript are used to access elements in an array or object. For example, if you have an array of numbers, you can access the first element by using the square brackets and the index of the element you want to access, like this:

var numbers = [1, 2, 3, 4, 5];
var firstNumber = numbers[0];

In this example, the firstNumber variable will be assigned the value of 1, which is the first element in the array. The same syntax can be used to access elements in an object, like this:

var person = {
  name: 'John',
  age: 30
};

var name = person['name'];

In this example, the name variable will be assigned the value of ‘John’, which is the value of the ‘name’ property in the person object.

Square brackets can also be used to create a new array, like this:

var numbers = [1, 2, 3, 4, 5];

In this example, the numbers variable will be assigned an array containing the numbers 1 through 5.

Square brackets can also be used to create a new object, like this:

var person = {
  name: 'John',
  age: 30
};

In this example, the person variable will be assigned an object containing the properties ‘name’ and ‘age’.

So, to answer the question, the square brackets in JavaScript are used to access elements in an array or object, create a new array or object, and assign values to variables.