isabella232 / jscodemods

Collection of jscodeshift transformation scripts used by DataFox.

jscodemods

This repository contains jscodeshift tranformation scripts used by DataFox.

decaffeinate

Tranformation scripts in the decaffeinate directory are scripts meant to be run on decaffeinate tranpiled CoffeeScript -> ES6 code. These scripts are mainly meant to fix style rather than correctness. The style issues are mainly those imposed by the Airbnb JavaScript style guide that were unable to be fixed by eslint --fix in the bulk-decaffeinate process. These scripts are operating on files run with decaffeinate's --keep-commonjs and --prefer-const flags on.

fix-multi-assign-class-export

CoffeeScript source

module.exports = class Foo

Decaffeinated JavaScript

let Foo;
module.exports = Foo = class Foo {};

Fixed JavaScript

module.exports = class Foo {};

fix-class-assign-construct

CoffeeScript source

module.exports = class Foo

new Foo()

Decaffeinated JavaScript

let Foo;
module.exports = Foo = class Foo {};

Fixed JavaScript

module.exports = class Foo {};

fix-implicit-return-assignment

CoffeeScript source

class Foo
  setBar: (bar) ->
    this.bar = 42

Decaffeinated JavaScript

class Foo {
  setBar(bar) {
    return this.bar = 42;
  }
}

Fixed JavaScript

class Foo {
  setBar(bar) {
    this.bar = 42;
  }
}

fix-existential-conditional-assignment

CoffeeScript source

bar = foo() ? ''

Decaffeinated JavaScript

let left;
const bar = (left = foo()) != null ? left : '';

Fixed JavaScript

const bar = foo() || '';

fix-for-of-statement

CoffeeScript source

Note: This will skip over any for..of statements that contain a break or return since it cannot easily be converted into a forEach.

for x in [1, 2, 3, 4, 5]
  continue if x % 2 == 0
  console.log(x)

Decaffeinated JavaScript

for (let x of [1, 2, 3, 4, 5]) {
  if ((x % 2) === 0) { continue; }
  console.log(x);
}

Fixed JavaScript

[1, 2, 3, 4, 5].forEach((x) => {
  if ((x % 2) === 0) {
    return;
  }
  console.log(x);
});

remove-coffeelint-directives

CoffeeScript source

describe('SearchListService', () =>
  # declare queryBuilderObj
  ### coffeelint-variable-scope-ignore ###
  queryBuilderObj = null
  # ...
)

Decaffeinated JavaScript

describe('SearchListService', () => {
  // declare queryBuilderObj
  /* coffeelint-variable-scope-ignore */
  let queryBuilderObj;
  return queryBuilderObj = null;
  // ...
});

Fixed JavaScript

describe('SearchListService', () => {
  // declare queryBuilderObj
  let queryBuilderObj;
  return queryBuilderObj = null;
  // ...
});

bind-iteratee-and-callback-methods

Works with common Array.prototype, underscore _, async, and StreamWorker functions. Does not work with tasks in async control flow functions.

NOTE: This assumes that you have unbound all your bound methods prior to running this transform. You can do so by running find . -name "*.coffee" | xargs perl -pi -e 's/^( \w+:.*)=>$/\1->/g' on all your CoffeeScript source files.

CoffeeScript Source

class MultiplierService
  constructor: ->
    this.multiplier = 42
  # Originally a bound method:
  #   multiply: (x) =>
  multiply: (x) ->
    return x * @multiplier
  multiplyAll: (xs) ->
    return xs.map(@multiply)

xs = [1, 2, 3]
ms = new MultiplierService()

# Direct usage
xs.map(ms.multiply)

# Assigning to a variable prior to usage
doWork = ms.multiply
xs.map(multiply)
multiply(1)

Decaffeinated JavaScript

class MultiplierService {
  constructor() {
    this.multiplier = 42;
  }
  // Originally a bound method:
  //   multiply: (x) =>
  multiply(x) {
    return x * this.multiplier;
  }
  multiplyAll(xs) {
    return xs.map(this.multiply);
  }
}

const xs = [1, 2, 3];
const ms = new MultiplierService();

// Direct usage
xs.map(ms.multiply);

// Assigning to a variable prior to usage
const doWork = ms.multiply;
xs.map(doWork);
doWork(1);

Fixed JavaScript

class MultiplierService {
  constructor() {
    this.multiplier = 42;
  }
  // Originally a bound method:
  //   multiply: (x) =>
  multiply(x) {
    return x * this.multiplier;
  }
  multiplyAll(xs) {
    return xs.map(this.multiply.bind(this));
  }
}

const xs = [1, 2, 3];
const ms = new MultiplierService();

// Direct usage
xs.map(ms.multiply.bind(ms));

// Assigning to a variable prior to usage
const doWork = ms.multiply.bind(ms);
xs.map(doWork);
doWork(1);

ember-styleguide

Tranformation scripts in the ember-styleguide directory are scripts meant to be run on ES6 ember-cli code. These scripts are mainly meant to fix style rather than correctness. The style issues are mainly those imposed by the NetGuru Ember Style Guide.

fix-local-modules

Original JavaScript

import Ember from 'ember';

export default Ember.Component.extend({
  foo: Ember.computed(function() {}),
});

Fixed JavaScript

import Ember from 'ember';

const {Component, computed} = Ember;

export default Component.extend({
  foo: computed(function() {}),
});

fix-use-ember-get-and-set

Original JavaScript

import Ember from 'ember';

export default Ember.Component.extend({
  foo: Ember.computed('bar', function() {
    return this.get('bar');
  }),
});

Fixed JavaScript

import Ember from 'ember';

const {get} = Ember;

export default Ember.Component.extend({
  foo: Ember.computed('bar', function() {
    return get(this, 'bar');
  }),
});

transforms

These are some miscellaneous transforms.

fix-class-assign-construct

This should be run if you have classes that are assigned to some identifier and then the identifier is used in the file to construct the class.

Original JavaScript

module.exports = (class FooScript { });

if (!module.parent) {
  const script = new module.exports();
}

Fixed JavaScript

class FooScript { };
module.exports = FooScript;

if (!module.parent) {
  const script = new FooScript();
}

use-strict

Adds a top-level 'use strict' statement to JavaScript files. If you are doing this with bulk-decaffeinate, you should run eslint --fix afterwards since bulk-decaffeinate puts a comment directly before the 'use strict'; directive.

Borrowed from cpojer/jscodemod;