babel-plugin-inline-functions

babel-plugin-inline-functions

• NAME
• INSTALLATION
• SYNOPSIS
• DESCRIPTION
• OPTIONS
  • comment
  • label
  • prefix
  • remove
• USAGE
  • .babelrc
  • CLI
  • API
• DEVELOPMENT
  • NPM Scripts
• COMPATIBILITY
• CAVEATS
• SEE ALSO
• VERSION
• AUTHOR
• COPYRIGHT AND LICENSE

NAME

babel-plugin-inline-functions - a Babel plugin to inline selected functions

INSTALLATION

$ npm install babel-plugin-inline-functions

SYNOPSIS

$ cat test.js

function __INLINE__coalesce (value) {
    return value ?? ''
}

const foo = __INLINE__coalesce(options.foo)

$ babel --plugins inline-functions test.js

const foo = options.foo ?? ''

DESCRIPTION

This is a Babel plugin which inlines calls to selected functions within the scope in which the functions are declared. Only functions which contain a single return statement are inlined. Arguments passed to inlined functions are substituted for the corresponding parameters in the function body and (by default) the original function is removed.

Functions can be marked for inlining by using a custom prefix in the function name, a comment before the function declaration, or a label for the return statement in the function's body. By default, functions whose names begin with "__INLINE__" are inlined, but this can be modified or disabled via the plugin's options.

OPTIONS

The following plugin options are supported.

comment

• Type: string | false
• Default: false

Select functions for inlining by the presence of a block comment before the function keyword in the declaration. If set, the comment body is trimmed and compared to the option's value, and, if equal, the function is inlined. If set to false (as it is by default), function declaration comments are not checked.

Config

{
    "plugins": [
        ["inline-functions", {
            "comment": "inline"
        }]
    ]
}

Input

/* inline */ function coalesce (value) {
    return value ?? ''
}

const foo = coalesce(options.foo)

Output

const foo = options.foo ?? ''

label

• Type: string | false
• Default: false

Select functions for inlining by the presence of a label with this name before the return statement. If set to false (as it is by default), return statement labels are not checked.

Config

{
    "plugins": [
        ["inline-functions", {
            "label": "inline"
        }]
    ]
}

Input

function coalesce (value) {
    inline: return value ?? ''
}

const foo = coalesce(options.foo)

Output

const foo = options.foo ?? ''

prefix

• Type: string | false
• Default: "__INLINE__"

Select functions for inlining whose names start with the specified prefix. If set to false, function names are not checked.

Config

{
    "plugins": [
        ["inline-functions", {
            "prefix": "__inline__"
        }]
    ]
}

Input

function __inline__coalesce (value) {
    return value ?? ''
}

const foo = __inline__coalesce(options.foo)

Output

const foo = options.foo ?? ''

remove

• Type: boolean
• Default: true

Remove the inlined function declaration. If set to false, the declaration is preserved.

Config

{
    "plugins": [
        ["inline-functions", {
            "remove": false
        }]
    ]
}

Input

function __INLINE__coalesce (value) {
    return value ?? ''
}

const foo = __INLINE__coalesce(options.foo)

Output

function __INLINE__coalesce (value) {
    return value ?? ''
}

const foo = options.foo ?? ''

USAGE

.babelrc

$ cat .babelrc

{
    "plugins": ["inline-functions"]
}

CLI

$ babel --plugins inline-functions script.js

API

require('@babel/core').transform(code, {
    plugins: ['inline-functions']
})

DEVELOPMENT

NPM Scripts

The following NPM scripts are available:

• doctoc - generate the TOC (table of contents) in the README
• test - run the test suite

COMPATIBILITY

• Babel 6+ (only Babel 7+ is tested/supported)
• Maintained node versions

CAVEATS

• inlining may bloat your code
• inlining may not speed things up and may even slow things down¹
• only works with functions that have a single return statement and simple (i.e. non-destructuring) parameters: keep things simple

¹ Particularly on v8, which may have a better idea of what should be inlined when, and the memory/speed tradeoffs, than the developer.

SEE ALSO

• babel-plugin-nofn - convert some array-method calls to inline loops

VERSION

1.0.1

AUTHOR

• Emile Cantin
• chocolateboy - maintainer

COPYRIGHT AND LICENSE

Copyright © 2016-2020 by Emile Cantin.

This is free software; you can redistribute it and/or modify it under the terms of the ISC License.

Changelog

1.0.1 - 2020-05-31

• fix package name in the examples