Support elm-format 0.8 (and hence Elm 0.19)

CHANGELOG.md

@@ -1,16 +1,29 @@
+## 0.4.0 (ongoing)
+
+- Upgrade `elm-format` to `0.8` to support Elm `0.19` ([#4](https://github.com/gicentre/prettier-plugin-elm/issues/4))
+
+  This includes replacing `module Main exposing (..)` with `module Main exposing (something)` in tests, because this is what the new version of `elm-format` produces.
+
+  To support formatting of Elm code in markdown blocks, `prettier-plugin-elm` passes `--elm-version=0.19` to `elm-format`.
+  If you use Elm `0.18`, please install `prettier-plugin-elm@0.3`.
+
+- Internal:
+  - Upgrade dev dependencies
+  - Add pre-push git hook via [`husky`](https://github.com/typicode/husky) to avoid dumb linting errors in CI.
+
 ## 0.3.0 (2018-05-23)
 
-* Implement caching mechanism to speed-up formatting of Elm blocks in markdown files ([#3](https://github.com/gicentre/prettier-plugin-elm/issues/3))
+- Implement caching mechanism to speed-up formatting of Elm blocks in markdown files ([#3](https://github.com/gicentre/prettier-plugin-elm/issues/3))
 
-* Simplify `locStart()` and `locEnd()` ([#2](https://github.com/gicentre/prettier-plugin-elm/issues/2))
+- Simplify `locStart()` and `locEnd()` ([#2](https://github.com/gicentre/prettier-plugin-elm/issues/2))
 
-* Configure automatic testing on Windows using [AppVeyor](http://appveyor.com/).
+- Configure automatic testing on Windows using [AppVeyor](http://appveyor.com/).
 
 ## 0.2.2 & 0.2.1 & 0.2.0 (2018-04-12)
 
-* Switch to `elm-format@0.7.0-exp`
-* Use correct instance of `elm-format` when globally installed with npm ([#1](https://github.com/gicentre/prettier-plugin-elm/issues/1))
-* Fix ` ```markdown ` syntax highlighting on GitHub and NPM
+- Switch to `elm-format@0.7.0-exp`
+- Use correct instance of `elm-format` when globally installed with npm ([#1](https://github.com/gicentre/prettier-plugin-elm/issues/1))
+- Fix ` ```markdown ` syntax highlighting on GitHub and NPM
 
 ## 0.1.0 (2018-03-16)
 

README.md

@@ -84,6 +84,9 @@ main =
 ```
 ````
 
+In order to successfully format Elm code in markdown blocks, `prettier-plugin-elm` assumes your Elm version is 0.19.
+If you use Elm 0.18, please install `prettier-plugin-elm@0.3`.
+
 ## Getting started
 
 Simply install `prettier` and `prettier-plugin-elm` as your project’s npm dependencies:
@@ -156,10 +159,10 @@ If you’re interested in contributing to the development of Prettier for Elm, y
 
 To test it out on an Elm file:
 
-* Clone this repository.
-* Run `yarn`.
-* Create a file called `prettier-test.elm` or `prettier-test.md`.
-* Run `yarn prettier prettier-test.elm` or `yarn prettier prettier-test.md` to check the output.
+- Clone this repository.
+- Run `yarn`.
+- Create a file called `prettier-test.elm` or `prettier-test.md`.
+- Run `yarn prettier prettier-test.elm` or `yarn prettier prettier-test.md` to check the output.
 
 ## Credits
 

package.json

@@ -25,21 +25,22 @@
     "prepublishOnly": "yarn lint && yarn test"
   },
   "devDependencies": {
-    "eslint": "^4.19.1",
-    "eslint-config-prettier": "^2.9.0",
-    "eslint-plugin-import": "^2.11.0",
-    "eslint-plugin-jest": "^21.15.0",
-    "eslint-plugin-prettier": "^2.6.0",
-    "jest": "^22.4.3",
-    "jest-runner-eslint": "^0.4.0",
-    "prettier": "^1.12.0",
+    "eslint": "^5.6.0",
+    "eslint-config-prettier": "^3.0.1",
+    "eslint-plugin-import": "^2.14.0",
+    "eslint-plugin-jest": "^21.22.0",
+    "eslint-plugin-prettier": "^2.6.2",
+    "jest": "^23.6.0",
+    "jest-runner-eslint": "^0.6.0",
+    "prettier": "^1.14.2",
     "prettier-check": "^2.0.0",
     "rimraf": "^2.6.2",
-    "sleep-promise": "^6.0.0"
+    "sleep-promise": "^8.0.1"
   },
   "dependencies": {
-    "elm-format": "0.7.0-exp",
-    "execa": "^0.10.0",
+    "elm-format": "^0.8.1-rc2",
+    "execa": "^1.0.0",
+    "husky": "^1.0.0-rc.14",
     "make-dir": "^1.3.0",
     "object-hash": "^1.3.0",
     "serialize-error": "^2.1.0",
@@ -51,5 +52,10 @@
   "prettier": {},
   "eslintIgnore": [
     "coverage"
-  ]
+  ],
+  "husky": {
+    "hooks": {
+      "pre-push": "yarn lint"
+    }
+  }
 }

src/parser.js

@@ -2,42 +2,47 @@
 
 const pkg = require("../package.json");
 const { getCachedValue } = require("./cache");
-const { formatTextWithElmFormat } = require("./util");
+const { formatTextWithElmFormat, getElmFormatVersion } = require("./util");
 
 /*
  * Simply passing text to elm-format is not enough because of two problems:
  *
- * 1. If the code chunk contains no symbol assignments, elm-format fails.
- * 2. `module Main exposing (..)` is always added if no module has been defined,
+ * 1. If the code chunk only contains an import statement, no formatting takes place.
+ *    Related to: https://github.com/avh4/elm-format/issues/551
+ * 2. `module Main exposing (.*)` is always added if no module has been defined,
  *    which is not wanted in markdown code blocks.
+ *    Related to: https://github.com/avh4/elm-format/issues/65
  *
- * Both problems are related to https://github.com/avh4/elm-format/issues/65.
- * Until this upstream issue is fixed, two custom patches are applied:
+ * Until the upstream issues are fixed, two custom patches are applied:
  *
- * 1. A temporary dummy statement is appended to text before sending it to elm-format.
- * 2. If elm-format's result defines a module while the source does not,
- *    module definition is trimmed while working with a markdown code block.
+ * 1. A dummy comment is added to the source and is then removed from the result.
+ * 2. If current context is a markdown block and the source does not declare a module,
+ *    module statement is removed from the result.
  *
  * Please submit an issue to https://github.com/gicentre/prettier-plugin-elm/issues
  * if there are any problems caused by the patches.
  */
 
-const dummyStatement = "\ndummyPrettierPluginElmSymbol = identity";
-const dummyStatementRegExp = /\s*dummyPrettierPluginElmSymbol =\s+identity\n$/;
-const autogeneratedModuleDefinitionRegExp = /[ \t]*module\s+Main\s+exposing\s+\(\s*\.\.\s*\)\s*/;
+const dummyComment = "\n{- DUMMY COMMENT BY PRETTIER-PLUGIN-ELM -}";
+const dummyCommentRemovalRegExp = /\n*\{- DUMMY COMMENT BY PRETTIER-PLUGIN-ELM -\}/;
+const autogeneratedModuleDefinitionRegExp = /[ \t]*module\s+Main\s+exposing\s+\([^)\n]*\)\s*/;
 
 function parse(text, parsers, opts) {
-  // patch 1 (step 1/2)
-  const textToSend = `${text}${dummyStatement}`;
+  // patch 1 step 1
+  const textToSend = `${text}${dummyComment}`;
 
   // extract formatted text from elm-format
   let formattedText = getCachedValue(formatTextWithElmFormat, [
     textToSend,
-    pkg.version
+    pkg.version,
+    getElmFormatVersion()
   ]);
 
-  // path 1 (step 2/2)
-  formattedText = formattedText.replace(dummyStatementRegExp, "\n");
+  // patch 1 step 2
+  formattedText = formattedText.replace(dummyCommentRemovalRegExp, "");
+  if (formattedText === "\n") {
+    formattedText = "";
+  }
 
   // patch 2
   if (

src/util.js

@@ -2,8 +2,20 @@
 
 const execa = require("execa");
 
+let cachedElmFormatVersion;
+function getElmFormatVersion() {
+  if (!cachedElmFormatVersion) {
+    // a cleaner way of getting elm-format version
+    // will be possible when this issue is closed:
+    // https://github.com/avh4/elm-format/issues/425
+    const help = execa.sync("elm-format", ["--help"]).stdout;
+    cachedElmFormatVersion = help.match(/elm-format ([^\n]+)/)[1];
+  }
+  return cachedElmFormatVersion;
+}
+
 function formatTextWithElmFormat(text) {
-  return execa.sync("elm-format", ["--stdin"], {
+  return execa.sync("elm-format", ["--stdin", "--elm-version=0.19"], {
     input: text,
     preferLocal: true,
     localDir: __dirname,
@@ -12,5 +24,6 @@ function formatTextWithElmFormat(text) {
 }
 
 module.exports = {
+  getElmFormatVersion,
   formatTextWithElmFormat
 };

test/caching.test.js

@@ -51,13 +51,13 @@ test(`correctly deals with cache`, () => {
       plugins: [path.resolve(__dirname, "..")]
     })
   ).toEqual(expectedFormattedText);
-  expect(spyForFormatTextWithElmFormat.mock.calls).toHaveLength(
+  expect(spyForFormatTextWithElmFormat.mock.calls.length).toBe(
     numberOfFormatCallsInFirstRun
   );
 
   return sleep(cacheGCInterval * 2).then(() => {
     // a call to formatTextWithElmFormat() that triggers garbage collection
-    prettier.format("", {
+    prettier.format("{- -}", {
       parser: "elm",
       plugins: [path.resolve(__dirname, "..")]
     });
@@ -69,7 +69,7 @@ test(`correctly deals with cache`, () => {
         plugins: [path.resolve(__dirname, "..")]
       })
     ).toEqual(expectedFormattedText);
-    expect(spyForFormatTextWithElmFormat.mock.calls).toHaveLength(
+    expect(spyForFormatTextWithElmFormat.mock.calls.length).toBe(
       numberOfFormatCallsInFirstRun + 1 /* for "" */ + 1 /* for GC-d block */
     );
   });

test/fixtures/hello-world.prettified.elm

@@ -1,4 +1,4 @@
-module Main exposing (..)
+module Main exposing (main)
 
 import Html exposing (text)
 

test/fixtures/leading-comment.prettified.elm

@@ -1,7 +1,7 @@
 {- a comment in Elm code -}
 
 
-module Main exposing (..)
+module Main exposing (main)
 
 import Html exposing (text)
 

test/fixtures/let-in.prettified.elm

@@ -1,7 +1,7 @@
 -- Source: https://github.com/avh4/elm-format/issues/350
 
 
-module Main exposing (..)
+module Main exposing (viewEntries)
 
 
 viewEntries : String -> List Entry -> Html Msg

test/fixtures/multiple-blocks.prettified.md

@@ -1,8 +1,8 @@
 ---
 id: "litvis"
 elm:
-    dependencies:
-        gicentre/elm-vega: latest
+  dependencies:
+    gicentre/elm-vega: latest
 ---
 
 <!-- source (with minor amendments): https://github.com/gicentre/litvis/blob/master/documents/tutorials/geoTutorials/geoFormats.md -->
@@ -631,6 +631,7 @@ graticule gStep =
         meridian lng =
             if round lng % 90 == 0 then
                 List.map (\lat -> ( lng, lat )) (range -90 90 (min 10 gStep))
+
             else
                 List.map (\lat -> ( lng, lat )) (range (gStep - 90) (90 - gStep) (min 5 gStep))