easel/plv8ify

Turn JS files into PLV8 functions

PLV8ify

Introduction

plv8ify bundles typescript/javascript input and writes SQL file(s) containing Postgres functions using PLV8.

Why

• Interchange code between API and Database
• Write code in Typescript and use it in Postgres

Example

1. npm install -g plv8ify
2. Sample input.ts

const { point: turfPoint } = require('@turf/helpers')

export function point(lat, long) {
  const pt = turfPoint([lat, long])
  return pt
}

3. Run plv8ify generate
4. Step 3 emits SQL file with names like ./plv8-dist/plv8ify_point.plv8.sql (one for each exported function)
5. Execute the generated ./plv8-dist/plv8ify_point.plv8.sql using a Postgres client
6. Call the generated function using a Postgres client SELECT plv8ify_point(52.5200,13.4050);
7. Steps 1-6 converted a Typescript file into a PLV8 executable function

CLI Arguments

Generate Command Flags	Type	Description	Default
--debug	Boolean	Print additional debug information	false
--write-esbuild-output	Boolean	Write the intermediate bundled Javascript output from ESBuild	false
--input-file	String	Specify an input file path (only Typescript supported at the moment)	input.ts
--output-folder	String	Specify an output folder	plv8ify-dist
--scope-prefix	String	Specify a scope prefix, by default plv8ify adds plv8ify_ as prefix for exported typescript functions	plv8ify
--fallback-type	String	Specify a fallback type when plv8ify fails to map a detected Typescript type to a Postges type	JSONB
--mode	'inline' or 'start_proc'	Bundle the library inline in each function or bundle the libary to be used with plv8.start_proc	inline

TODO

• README
• Custom function name
• Export multiple functions
• Input arguments - basic setup
• Flag to Emit intermediate file
• Input arguments - support most data types
• Input file name
• Output folder name
• Return type guessing
• Typescript as input
• Javascript as input
• Typescript for plv8ify code
• For each exported bundle, use tree-shaken bundle, currently, each bundle gets all of the Javascript
• Test cases

Caveats

• Very early, only a small number of types supported
• Only supports typescript as input at the moment
• Scaling an application server is easier than scaling a database server, moving the logic in database as postgres functions makes it easier (IMO SQL is declarative, like React for data) to call the code/do some things but you are effectively shifting compute from application server to database server which might be a bad idea in most cases.

Prior Art

• https://github.com/CSTARS/es6-to-plv8
• https://github.com/clkao/plv8x

Contact

If you want to reach out to me, please DM me on https://twitter.com/divyenduz or email me at mail at divyendusingh.com