To enable users to share their EBS snapshots with other AWS accounts and ensure that the shared snapshots are copyable, you can use the AWS SDK for JavaScript (AWS Amplify). Here's a JavaScript code snippet to achieve this [1][2]:

const AWS = require('aws-sdk');
const awsConfig = {
  accessKeyId: 'YOUR_ACCESS_KEY',
  secretAccessKey: 'YOUR_SECRET_KEY',
  region: 'us-east-1', // Replace with your desired region
};

AWS.config.update(awsConfig);

const ec2 = new AWS.EC2();

// Specify the EBS snapshot ID you want to share
const snapshotId = 'YOUR_SNAPSHOT_ID';

// Specify the AWS account IDs with which you want to share the snapshot
const targetAccountIds = ['AWS_ACCOUNT_ID_1', 'AWS_ACCOUNT_ID_2']; // Replace with the target account IDs

// Enable copy permissions for the shared snapshot
function modifySnapshotAttribute(snapshotId, attribute) {
  return new Promise((resolve, reject) => {
    const params = {
      Attribute: attribute,
      SnapshotId: snapshotId,
    };

    ec2.modifySnapshotAttribute(params, (err, data) => {
      if (err) {
        reject(err);
      } else {
        resolve(data);
      }
    });
  });
}

// Share the EBS snapshot with the specified AWS account IDs
function shareSnapshot(snapshotId, targetAccountIds) {
  return new Promise((resolve, reject) => {
    const params = {
      SnapshotId: snapshotId,
      Attribute: 'createVolumePermission',
      CreateVolumePermission: {
        Add: targetAccountIds.map((accountId) => ({ UserId: accountId })),
      },
    };

    ec2.modifySnapshotAttribute(params, (err, data) => {
      if (err) {
        reject(err);
      } else {
        resolve(data);
      }
    });
  });
}

(async () => {
  try {
    // Share the EBS snapshot with specified AWS accounts
    const shareResponse = await shareSnapshot(snapshotId, targetAccountIds);

    // Enable copy permissions for the shared snapshot
    const copyResponse = await modifySnapshotAttribute(snapshotId, 'createVolumePermission');

    console.log('EBS snapshot shared and copy permissions enabled successfully.');
  } catch (error) {
    console.error('Error sharing EBS snapshot:', error);
  }
})();

Before running this code, make sure to replace `YOUR_ACCESS_KEY, YOUR_SECRET_KEY, us-east-1, YOUR_SNAPSHOT_ID, and AWS_ACCOUNT_ID_1, 'AWS_ACCOUNT_ID_2` with your AWS credentials, region, the EBS snapshot ID you want to share, and the target AWS account IDs with which you want to share the snapshot.
This code first shares the EBS snapshot with the specified AWS accounts and then enables copy permissions for the shared snapshot. It uses promises for asynchronous operations to ensure that the sharing and permission modification steps are completed successfully.