Babel Plugin Defer Logic

JS equivalent of Golang's defer and Python's with statements.

Installation

yarn add --dev babel-plugin-defer-logic
# OR
npm install --save-dev babel-plugin-defer-logic

Setup

Add babel-plugin-defer-logic to your babel config's plugins section. Try to add it to the end so it runs the last transformations.

eg:

{
  "presets": ["@babel/preset", { "targets": { "node": 12 } }],
  "plugins": ["babel-plugin-defer-logic"]
}

Usage

This package converts the contents of defer calls to be in a function body's finally. Multiple arguments are supported and will be handled individually.

Function literals are supported, the body of the function is copied as a block to the finally part. Function references are treated as ordinary variables, so you'll have to do defer(myFunc()) instead of defer(myFunc)

You can however do

1defer(() => {
2  // This is good
3})
4defer(function() {
5  // This is good
6})
7defer(async function() {
8  // This is still good, as long as parent function is also an async function
9})

More usages:

1// From
2function hello() {
3  setIsLoading(true)
4  defer(setIsLoading(false))
5  // .. Do the work
6}
7// To
8function hello() {
9  try {
10    setIsLoading(true)
11    // .. Do the work
12  } finally {
13    setIsLoading(false)
14  }
15}
16
17function hello() {
18  try {
19    setIsLoading(true)
20    setIsConnected(false)
21    defer(setIsLoading(false))
22    defer(setIsConnected(true))
23    // .. Do the work
24  } catch (error) {
25    console.log(error)
26  }
27}
28// To
29function hello() {
30  try {
31    try {
32      setIsLoading(true)
33      setIsConnected(false)
34      // .. Do the work
35    } catch (error) {
36      console.log(error)
37    }
38  } finally {
39    setIsLoading(false)
40    setIsConnected(true)
41  }
42}

LICENSE

The contents of this package/repository are licensed under the terms of MIT License. See the LICENSE file for more info.