codemod-cli
codemod-cli is a command line tool for generating, testing, and publishing codemods.
Installation
npm install --global codemod-cli
# OR
yarn global add codemod-cli
Usage
The codemod-cli
workflow is focused on managing a group of codemods.
To get started you first need a project. You can generate a new codemod-cli project via:
codemod-cli new <project-name>
This will create a small project structure (README.md
, package.json
, etc) which is
ready to help you manage your codemods.
Once you have a project, you can generate a new codemod:
codemod-cli generate codemod <name of codemod> // jscodeshift js codemod
codemod-cli generate codemod <name of codemod> -t=hbs // ember-template-recast hbs codemod
This will setup a new codemod within your project at transforms/<name of codemod>/index.js
along with a test harness, README, fixture directory, and an initial set of input/output fixtures.
Once you have tweaked your codemod and its fixtures to your liking, it is time to run your tests:
codemod-cli test
As you develop your codemod you may need additional fixtures (e.g. to test various combinations of
inputs). To generate a new fixture, run the following:
codemod-cli generate fixture <name of codemod> <name of fixture>
This sets up two new files in transforms/<name of codemod>/__testfixtures__/
using the fixture name
you provided. These fixtures are used by the testing harness to verify that your codemod is working properly.
Once you have things just how you like them with your new codemod (and your tests are passing :wink:) you
can update your project's README and your transforms README via:
codemod-cli update-docs
File Types
By default the bin script that is generated for your codemod-cli
project will run against .js
and .ts
files.
If you'd like to change that (e.g. to run against .hbs
or .jsx
files) you can tweak your projects bin/cli.js
script
to add --extensions=hbs,jsx
:
#!/usr/bin/env node
'use strict';
require('codemod-cli').runTransform(
__dirname,
process.argv[2], ,
process.argv.slice(3),
'hbs,jsx'
)
Debugging Workflow
Oftentimes, you want to debug the codemod or the transform to identify issues with the code or to understand
how the transforms are working, or to troubleshoot why some tests are failing.
Hence we recommend a debugging work-flow like below to quickly find out what is causing the issue.
1. Place debugger
statements
Add debugger
statements, in appropriate places in the code. For example:
...
const params = a.value.params.map(p => {
debugger;
if(p.type === "SubExpression") {
return transformNestedSubExpression(p)
...
2. Inspect the process with node debug
Here we are going to start the tests selectively in node debug mode. Since the
codemod is bootstrapped using codemod-cli which is using jest in turn
to run the tests, jest is having an option -t <name-of-spec>
to run a particular
set of tests instead of running the whole test suite.
We are making use of both these features to start our tests in this particular fashion.
For more details on node debug, visit the official
Node.js debugging guide, and for jest documentation on tests, here
node --inspect-brk ./node_modules/.bin/codemod-cli test -t '<fixture-name>'
For example, if you want to debug the null-subexp.input.hbs
fixture or only that particular test case is failing
because of an issue.
node --inspect-brk ./node_modules/.bin/codemod-cli test -t 'null-subexp'
Sometimes we need to use --runInBand
flag for the debugger statements to be hit when focusing the test with jest
For example:
node --inspect-brk ./node_modules/.bin/jest --testNamePattern "ember-concurrency transforms correctly" --runInBand
Once you run the above command, your tests will start running in debug mode and your breakpoints will be
triggered appropriately when that particular block of code gets executed. You can run the debugger inside
Chrome browser dev-tools. More details on here
Contributing
Installation
git clone git@github.com:rwjblue/codemod-cli.git
cd codemod-cli
yarn
Linting
yarn lint:js
yarn lint:js --fix
Running tests
License
This project is licensed under the MIT License.