appwrite/app/sdks/web-javascript/docs/examples/database/get-document.md

let sdk = new Appwrite();

sdk
    .setProject('5df5acd0d48c2') // Your project ID
;

let promise = sdk.database.getDocument('[COLLECTION_ID]', '[DOCUMENT_ID]');

promise.then(function (response) {
    console.log(response); // Success
}, function (error) {
    console.log(error); // Failure
});