Check Consecutive Numbers in Array using JavaScript

To check for consecutive numbers like 100, 101, 102, etc., use the concept of reduce(). TRUE would be returned for consecutive numbers, else false is the return value.

Example

const sequceIsConsecutive = (obj) =>
Boolean(obj.reduce((output, lastest) => (output ?
(Number(output.number) + 1=== Number(lastest.number) ? lastest : false)
: false)));
console.log("Is Consecutive="+sequceIsConsecutive ([{ number: '100'
},{number: '101'} ,{number: '102' }]));
console.log("Is Consecutive="+sequceIsConsecutive([{ number: '100' },
{number: '102'} ,{number: '104' }]));

To run the above program, you need to use the following command −

node fileName.js.

Here, my file name is demo126.js.

Output

This will produce the following output −

PS C:\Users\Amit\JavaScript-code> node demo126.js
Is Consecutive=true
Is Consecutive=false