Add cli - generates css and writes to a file

.gitignore

@@ -4,4 +4,6 @@ elm-stuff/
 repl-temp-*
 .DS_Store
 */index.html
-index.html
+index.html
+node_modules
+

index.js

@@ -0,0 +1,99 @@
+var fs = require("fs");
+var tmp = require("tmp");
+var path = require("path");
+var compileElm = require("node-elm-compiler").compile;
+
+function generateCss(opts) {
+  assertOptionsPresent(opts);
+
+  return withTmpDir().then(tmpDirPath => {
+    var emitterFile = path.join(tmpDirPath, "StyleElementsEmitter.elm");
+    var destFile = path.join(tmpDirPath, "style-elements-emitter.js");
+    var emitterTemplate = buildEmitterTemplate(opts.stylesheetModule, opts.stylesheetFunction);
+
+    return writeFile(emitterFile, emitterTemplate)
+      .then(() => compile(emitterFile, { output: destFile, yes: true }))
+      .then(() => extractCssResults(destFile));
+  });
+}
+
+function assertOptionsPresent(opts = {}) {
+  var requiredOptions = ["stylesheetModule", "stylesheetFunction"];
+  var providedOptions = Object.keys(opts);
+  var missingOptions = requiredOptions.filter(o => !providedOptions.includes(o) || providedOptions[o] === "");
+
+  if (missingOptions.length > 0) {
+    throw new Error(`Missing options: ${missingOptions.join(', ')}`);
+  }
+}
+
+function withTmpDir() {
+  return new Promise(function(resolve, reject) {
+    tmp.dir({ unsafeCleanup: true }, function(err, tmpDirPath) {
+      if (err) {
+        reject(err);
+      } else {
+        resolve(tmpDirPath);
+      }
+    });
+  });
+}
+
+function buildEmitterTemplate(stylesheetModule, stylesheetFunction) {
+  return unindent(
+  4,
+  `
+    port module StyleElementsEmitter exposing (..)
+
+    import ${stylesheetModule}
+
+
+    port result : String -> Cmd msg
+
+
+    stylesheet =
+        ${stylesheetModule}.${stylesheetFunction}
+
+
+    main : Program Never () Never
+    main =
+        Platform.program
+            { init = ( (), result stylesheet.css )
+            , update = \\_ _ -> ( (), Cmd.none )
+            , subscriptions = \\_ -> Sub.none
+            }
+  `
+  );
+}
+
+function unindent(count, text) {
+  var spaces = new Array(count + 1).join(" ");
+  return text.replace(new RegExp(`^${spaces}`, "gm"), "");
+}
+
+function writeFile(...args) {
+  return new Promise((resolve, reject) => {
+    return fs.writeFile(...args, err => err ? reject(err) : resolve());
+  })
+}
+
+function compile(src, options) {
+  return new Promise(function(resolve, reject) {
+    compileElm(src, options).on("close", function(exitCode) {
+      if (exitCode === 0) {
+        resolve();
+      } else {
+        reject("Errored with exit code " + exitCode);
+      }
+    });
+  });
+}
+
+function extractCssResults(destFile) {
+  var emitter = require(destFile).StyleElementsEmitter;
+  var worker = emitter.worker();
+
+  return new Promise(resolve => worker.ports.result.subscribe(resolve));
+}
+
+module.exports = generateCss;

package.json

@@ -0,0 +1,29 @@
+{
+  "name": "style-elements",
+  "version": "3.2.3",
+  "description": "CSS Preprocoessor for Elm's style-elements",
+  "main": "index.js",
+  "bin": {
+    "style-elements": "./style-elements.js"
+  },
+  "directories": {
+    "example": "examples",
+    "test": "tests"
+  },
+  "dependencies": {
+    "chalk": "^2.0.1",
+    "commander": "^2.11.0",
+    "postcss": "^6.0.6",
+    "tmp": "0.0.31"
+  },
+  "devDependencies": {},
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "http://package.elm-lang.org/packages/mdgriffith/style-elements"
+  },
+  "author": "Oliver Searle-Barnes",
+  "license": "BSD-3-Clause"
+}

style-elements.js

@@ -0,0 +1,31 @@
+#!/usr/bin/env node
+
+var styleElements = require('./');
+var pkg = require('./package.json');
+var program = require('commander');
+var fs = require("fs");
+var chalk = require('chalk');
+
+program
+  .version(pkg.version)
+  .usage('[options] <stylesheetModule> <stylesheetFunction>')
+  .option('-o, --output [outputFile]', '(optional) file to write the CSS to', 'out.css')
+  .parse(process.argv);
+
+
+if(program.args.length !== 2) {
+  program.outputHelp();
+  process.exit(1);
+}
+else {
+  var [stylesheetModule, stylesheetFunction] = program.args;
+  styleElements({stylesheetModule, stylesheetFunction})
+    .then(result => writeFile(program.output, result))
+    .then(() => console.warn(chalk.green(`\n----> Success! styles were written to ${program.output}\n`)));
+}
+
+function writeFile(...args) {
+  return new Promise((resolve, reject) => {
+    return fs.writeFile(...args, err => err ? reject(err) : resolve());
+  })
+}