@effect/babel-plugin v0.2.0
@effect/babel-plugin
Why?
This Babel plugin helps to improve the performance of functional code written with the @fp-ts/*
and @effect/*
ecosystem of libraries.
There are two transformers contained within this plugin:
rewritePipe
rewriteIdentity
Installation
npm install -D @effect/babel-plugin
or
yarn add -D @effect/babel-plugin
or
pnpm install -D @effect/babel-plugin
Usage
Via .babelrc
(Recommended)
.babelrc
{
"plugins": ["@effect/babel-plugin"]
}
Via CLI
babel --plugins @effect/babel-plugin script.js
Via Node API
require("babel-core").transform("pipe(a, f(() => b))", {
plugins: ["@effect/babel-plugin"],
})
The following configuration options can also be passed to @effect/babel-plugin
:
/**
* The configuration options for `@effect/babel-plugin`.
*/
export interface PluginConfig {
/**
* Rewrites calls to `pipe` to directly call the piped functions.
*
* By default, the plugin will only rewrite calls to `pipe` imported from
* `@fp-ts/core/Function`. However, the `targetImports` configuration option
* can be used to allow the plugin to rewrite calls to `pipe` imported from
* custom paths.
*/
readonly rewritePipe?: false | {
targetImports: ReadonlyArray<string>
}
/**
* Rewrites calls to `identity` to remove them entirely.
*
* By default, the plugin will only rewrite calls to `identity` imported from
* `@fp-ts/core/Function`. However, the `targetImports` configuration option
* can be used to allow the plugin to rewrite calls to `identity` imported
* from custom paths.
*/
readonly rewriteIdentity?: false | {
targetImports: ReadonlyArray<string>
}
}
Transformers
Rewrite Pipe
The objective of this Babel transformer is to improve the performance of pipeable APIs by re-writing calls to pipe
at compile time to directly call the piped methods.
Concretely, this results in the following code example:
pipe(a, f(() => b), g(() => c))
being transformed into direct calls to the previously piped functions:
g(() => c)(f(() => b)(a))
Calls to pipe
are considered CallExpression
s in the Babel AST. To ensure that all calls to pipe are re-written correctly, the following cases are handled:
- When
pipe
is imported as a variable from a module and referenced as anIdentifier
in the AST - When
pipe
is imported as a namespace from a module and referenced as part of aMemberExpression
Rewrite Identity
The objective of this Babel transformer is to improve the performance of
pipeable APIs by re-writing calls to identity
at compile time to remove
them entirely
Concretely, this results in the following code example:
identity(a)
being transformed to remove calls to identity
:
a;
Calls to identity
will also be removed when part of a pipe
call:
pipe(a, identity, f(() => b))
will be transformed to:
f(() => b)(a);