TypeScript - add key / value pair to object

In this article, we would like to show you how to add key / value pair to an object in TypeScript.

In the below example we create object with two key / value pairs.
We add key3 with 'value3' using square bracket notation, then we display whole object .

Note:
This approach is useful because you can replace 'key3' string with some variable which let us address key value dynamically using variable.

Runnable example:

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interface MyObject {

  key1: string;

  key2: string;

}

​

const object: MyObject = {

  key1: 'value1',

  key2: 'value2',

};

​

object['key3'] = 'value3';

​

console.log(JSON.stringify(object, undefined, 4));

Output:

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{

    "key1": "value1",

    "key2": "value2",

    "key3": "value3"

}