Blob-common NPM

NPM module for common functions in backend

useful in a setup with

All functions can be imported from their respective modules (results in lowest packages size), e.g.:

import { sleep } from 'blob-common/core/sleep';
import { btoa } from 'blob-common/core/base64';

All functions can be imported directly from the core, e.g.:

import { sleep, btoa } from 'blob-common';

NB: the sanitize function is not included in the core, due to the relatively large size of imported package.

Module	Function	Description
`/base64`	`otob(object)`	takes an object and coverts to base64 string
`/base64`	`btoa(base64String)`	inverse: takes a base64 string and returns an object
`/date`	`now()`	returns a string of the current date in format `yyyy-mm-dd`
`/date`	`diffDate(dateStr, days)`	takes a dateStr in standard format and difference, returns a dateStr in the standard format
`/date`	`expireDate(dateStr)`	takes a dateStr in standard format and returns a date 30 days later in the standard format
`/handler`	`handler(lamdba)`	wrapper function for event handler (to log errors)
`/handler`	`getUserFromEvent(event)`	returns the userId (from AWS cognito user pool) of authenticated User
`/handler`	`apiCall(promise)`	async wrapper for promise, returns the a tuple `[err, result]`
`/ids`	`newPhotoId()`	returns a newly generated photoId (starts with `P`)
`/ids`	`newGroupId()`	returns a newly generated groupId (starts with `G`)
`/ids`	`newAlbumId()`	returns a newly generated albumId (starts with `A`)
`/RND`	`RND`	returns a random number between 1 and 15, usable as an index key in dynamoDb to spread database load on very large queries
`/sleep`	`sleep(ms)`	`await sleep(1000)` sleeps for 1 second. Used in tests to wait for dynamoDB to have processed updates
`/sanitize`	`sanitize(dirty)`	sanitizes a string from any sequences that may cause security issues (e.g. when using name string in an email message)

Module	Function	Description
`/db`	`dynamoDb.get(params)`	returns a promise for DynamoDb function using the `params`. Uses AWS-SDK, refer to official docs for more info. Also has functions `.put`, `.update`, `.delete`, `query`, `transact` (for `TransactWrite`)
`/db`	`dbUpdate(PK, SK, key, newVal)`	returns a promise for a single update on the database, setting `key` to new value provided in `newVal`
`/db`	`dbUpdateMulti(PK, SK, newKV)`	returns a promise for a single update on the database at multiple keys. `newKV` is an object containing keys to be updated with new values
`/dbClean`	`cleanRecord(object)`	removes keys `RK`, `datePK`, `dateSK`, `cognitoId` from the object - useful for storing data as derived items in other items (e.g. owner as part of photo object)
`/dbCreate`	`dbItem(object)`	returns an object with extended keys for database: `createdAt`, `RK`, `datePK`, `dateSK`
`/dbCreate`	`dbCreateItem(object)`	returns a promise to create an expanded item in database from object (object must have `PK` and `SK` keys)

Some caveats on the specific dynamoDB functions:

eu-central-1 is the standard region chosen
to work, there should be a process.env.photoTable variable for all functions (except dynamoDb)
database must have PK (string) as primary key, and SK (string) as sortkey

Module	Function	Description
`/s3`	`s3.getMetadata(params)`	returns a promise for an s3 function using the params.
`/s3`	`s3.delete(params)`	deletes stuff.
`/s3`	`s3.get(params)`	gets an object.
`/s3`	`s3.list(params)`	lists a bucket probably.
`/s3`	`s3.getSignedUrl(params)`	gets a signed url for ADDING a file to s3 (for uploads).
`/s3`	`s3.getSignedUrlGet(params)`	gets a signed url for READING a file from s3.
`/ses`	`ses.send(params)`	sends an email from ses using params - returns promise
`/ses`	`ses.sendEmail(params)`	sends an email from ses using `{toEmail, fromEmail, subject, data, textData}` - returns promise

NB:

Caveats:

s3 function uses s3 bucket specified in process.env.photoBucket or process.env.devBucket

Module	Function	Description
`/email`	`emailBody(rows)`	returns email body with rows
`/email`	`row(cells)`	generic row containing array of cells
`/email`	`headerRow(logoSrc, frontendUrl)`	header row with logo, links to frontend
`/email`	`footerRow`
`/email`	`photoRow(photoSrc, linkUrl)`	row containing (header) photo
`/email`	`textCell(subtype)`	cell containing `greeting`, `paragraph` or `buttonEscape` (small text with link)
`/email`	`dividerCell(dividerSrc)`
`/email`	`buttonCell(text, link)`
`/email`	`codeCell(code)`	big text block centered with code
`/email`	`signatureCell(src)`	left aligned signature under email
`/email`	`greeting(text)`
`/email`	`paragraph(text)`
`/email`	`buttonEscape(url)`
`/email`	`makeEmailSrc(url, width, height)`	returns publicly accessible url for image in S3 bucket

Caveats:

makeEmailSrc uses s3 bucketname from process.env.bucket or process.env.devBucket

Module	Function	Description
`/cognito`	`cognito.disableUser(userId)`	disables a user in the cognito user pool
`/cognito`	`cognito.deleteUser(userId)`	deletes a user in the cognito user pool

Caveats: