@cozy/codemods

Cozy codeshifts

A collection of utils and transforms for jscodeshift.

Codeshifts are automatic transformations of Javascript code. They can be used for

• code migrations following API changes
• flag removal
• general automatic code changes...

Documentation

See jscodeshift-docs for more information on codeshifts.

Here are nice examples about import manipulation and React & JSX manipulation.

The API doc can be usefull too.

Installation

You can install @cozy/codemods globally so that you do not have to pollute your package.json and yarn.lock in every project where you use it.

yarn global add @cozy/codemods

General usage

$ cozy-codemods --help
$ cozy-codemods list # List available transforms
$ cozy-codemods showExample apply-flag # Show an example of what a transform does
$ cozy-codemods run apply-flag -- --flag=my-flag # Run a transform, pass jscodeshift args after --

Available transforms

Apply flag

Transforms flag() calls into true then remove dead code and dead imports

Before

import Old from 'old'
import New from 'new'
flag("hello") ? <Old /> : <New />

After

import New from 'new'
<New />

Remove boolean variables

Simpler version of Apply flag only for boolean variables.

Before

import Old from 'old'
import New from 'new'
true ? <Old /> : <New />

After

<New />

Utils

• Replace a HOC with a hook with hoc-replacer.js
• Remove unused imports with remove-unused-imports.js

API

Functions

removeUnusedImports(root, j)

Removes unused imports by counting usage. JSX identifiers are counted as React usage.

isBlockLike(path) ⇒ Boolean

Returns true if path is Program or a Block

flatReplace(path, newNode)

Replaces path.node with newNode without keeping blocks, flattening newNode into path. Useful when removing if/else.

simplifyConditions(root, j)

Statically evaluates boolean conditions

removeUnusedImports(root, j)

Removes unused imports by counting usage. JSX identifiers are counted as React usage.

Kind: global function

Param	Type
root	PathNode
j	Object

isBlockLike(path) ⇒ Boolean

Returns true if path is Program or a Block

Kind: global function

Param	Type
path	PathNode

flatReplace(path, newNode)

Replaces path.node with newNode without keeping blocks, flattening newNode into path. Useful when removing if/else.

Kind: global function

Param	Type
path	PathNode
newNode	Node

simplifyConditions(root, j)

Statically evaluates boolean conditions

Kind: global function

Param	Type
root	NodePath
j	Object

Example

`if (true) { foo } else { bar }` -> `foo`

`true ? foo : bar` -> `foo`

`!true ? foo : bar` -> `bar`