Check if key exists in javascript

You can check if a key is available in JavaScript using the hasOwnProperty method or

the in operator. Here's an example of how to use both methods:

1. Using the hasOwnProperty method:

const obj = { key1: 'value1', key2: 'value2' };
if (obj.hasOwnProperty('key1')) {
  console.log('Key "key1" is available in the object');
} else {
  console.log('Key "key1" is not available in the object');
}

2. Using the in operator:

const obj = { key1: 'value1', key2: 'value2' };
if ('key1' in obj) {
  console.log('Key "key1" is available in the object');
} else {
  console.log('Key "key1" is not available in the object');
}

Both methods will check if the key "key1" is available in the object obj and provide the appropriate output based on its availability.

way to check key is available in javascript array object

Here's an example of how to check if a key (index) is available in a JavaScript array:

1. Using the hasOwnProperty method:

const arr = ['value1', 'value2', 'value3'];
const index = 1;
if (arr.hasOwnProperty(index)) {
  console.log(`Index ${index} is available in the array`);
} else {
  console.log(`Index ${index} is not available in the array`);
}

1. Using the in operator:

const arr = ['value1', 'value2', 'value3'];
const index = 1;
if (index in arr) {
  console.log(`Index ${index} is available in the array`);
} else {
  console.log(`Index ${index} is not available in the array`);
}

Both methods will check if the index is available in the array arr and provide the appropriate output based on its availability.