What is the way to add a key/value pair to a Javascript object?

Question

This is my object literal:

var obj = {key1: value1, key2: value2};

Can you tell me how to add key3 with value3 to the object?

Answer 1

It can be done in two ways:

var obj = {

    key1: value1,

    key2: value2

};

Dot notation:

obj.key3 = "value3";

Square bracket notation:

obj["key3"] = "value3";

When the name of the property is known, the first form is used. We use a second form when the name of the property is dynamically determined.

var getProperty = function (propertyName) {

    return obj[propertyName];

};

getProperty("key1");

getProperty("key2");

getProperty("key3");

We can construct a real JavaScript array either by using:

The Array literal notation:

var arr = [];

The Array constructor notation:

var arr = new Array();

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