create one aws alarm for multiple functions in javascript

To create one AWS CloudWatch alarm for multiple functions in JavaScript, you can use the AWS SDK for JavaScript. Here's a step-by-step guide:

1. Install the AWS SDK for JavaScript in your project by running npm install aws-sdk.

2. Import the required AWS SDK modules in your JavaScript file:

index.tsx
const AWS = require('aws-sdk');
AWS.config.update({ region: 'your-region' }); // replace 'your-region' with your desired AWS region
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3. Create an instance of the CloudWatch class:

index.tsx
const cloudWatch = new AWS.CloudWatch();
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4. Define the parameters for your alarm, such as the metric to monitor, threshold values, and alarm actions:

index.tsx
const params = {
  AlarmName: 'YourAlarmName',
  ComparisonOperator: 'GreaterThanThreshold',
  EvaluationPeriods: 1,
  MetricName: 'YourMetricName',
  Namespace: 'AWS/Lambda',
  Period: 60,
  Threshold: 100,
  AlarmDescription: 'YourAlarmDescription',
  AlarmActions: ['arn:aws:sns:your-topic-arn']
};
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Replace YourAlarmName, YourMetricName, YourAlarmDescription, and arn:aws:sns:your-topic-arn with your desired values.

5. Create the alarm using the putMetricAlarm method:

index.tsx
cloudWatch.putMetricAlarm(params, function(err, data) {
  if (err) {
    console.log('Error creating alarm', err);
  } else {
    console.log('Alarm created successfully', data);
  }
});
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Make sure to handle any errors in the callback function.

This code snippet creates an alarm in CloudWatch that will trigger an action (such as sending a notification to an SNS topic) if the specified metric exceeds the threshold. You can use this code to create alarms for multiple functions by repeating steps 4 and 5 for each function.

Remember to replace the placeholder values with your own values, such as the region, alarm name, metric name, alarm description, and SNS topic ARN.

Note: Before creating the alarm, make sure that your functions are publishing the required metrics to CloudWatch for the chosen namespace.

Reference: AWS SDK for JavaScript Documentation - CloudWatch