Fundamentals of Objects in JS

Object is a non-primitive data type in JavaScript which consists of key-value pairs. Objects are mutable in nature, we will discuss about this in a minute. Every time we use {} (open and close curly braces) syntax we create a brand new object, let us look at the proof of this statement in the following image.

Keys

The keys of the object are of String type and case sensitive for example:

let person = {
    age: 27,
    Age: 200,
}

In the person object both the keys are valid and JavaScript does not throw an error.

Values

The value of the keys in an object can be of any data type.

let objectWithUniqueType = {
string: "string",
number: "number",
boolean: true,
weirdOne: null,
lessWeirdOne: undefined,
functionType: function () {
    return 'hello world!'
},
object: {
    name: 'I am an object',
},
arrays: [1,2,3,4,5],
rarelyUsed: Symbol('I am a Symbol'),
}

Accessing object values

We can access the objects values in the following ways:

Let us access values from avenger object.

const avenger = {
    name: 'Thor',
    ability: 'Thor can use lighting :zap:️ to save people from danger',
    location: 'Unknown',
    famousDialouge: function () {
        return 'Bring me Thanos!!:zap:️:zap:️:zap:️:zap:️:zap:️'
    },
}

The format we follow for accessing object values is objectName.key assuming there is a valid key, if the key we are trying to access is not defined in an object then we would get the value undefined

console.log(avenger.name)
// "Thor"
console.log(avenger.sibilings)
// undefined

We can use objectName["key"] syntax for getting values from an object as shown in the code snippet below.

console.log(avenger["name"])
// "Thor"
console.log(avenger["sibilings"])
// undefined

In this blog we have covered the basics of objects in JS, in the following blogs posts we will look into the nuances of objects and how we as developers can leverage the features of objects while building applications.

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