Set initial preprocessor

Author: Michael Vurchio

LICENSE

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+MIT License
+
+Copyright (c) 2020 micantoine
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

index.js

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+const path = require('path')
+const { interpolateName } = require('loader-utils')
+
+const pluginOptions = {
+  includePaths: [],
+  localIdentName: '[local]-[hash:base64:6]'
+}
+
+const regex = {
+  module: /\$style\.(:?[\w\d-]*)/gm,
+  style: /<style(\s[^]*?)?>([^]*?)<\/style>/gi
+};
+
+function generateName(resourcePath, styles, className) {
+  const filePath = resourcePath
+  const fileName = path.basename(filePath)
+  const localName = pluginOptions.localIdentName.length
+    ? pluginOptions.localIdentName.replace(/\[local\]/gi, () => className)
+    : className
+
+  const content = `${styles}-${filePath}-${fileName}-${className}`
+
+  let interpolatedName = interpolateName({ resourcePath }, localName, { content })
+
+  // prevent class error when the generated classname starts from a non word charater
+  if (/^(?![a-zA-Z_])/.test(interpolatedName)) {
+    interpolatedName = `_${interpolatedName}`
+  }
+
+  // prevent svelte "Unused CSS selector" warning when the generated classname ends by `-`
+  if (interpolatedName.slice(-1) === '-') {
+    interpolatedName = interpolatedName.slice(0, -1)
+  }
+
+  return interpolatedName
+}
+
+const markup = async ({ content, filename }) => {
+  const code = content;
+
+  if (pluginOptions.includePaths.length) {
+    for (const includePath of pluginOptions.includePaths) {
+      if (filename.indexOf(path.resolve(__dirname, includePath)) === -1) {
+        return { code };
+      }
+    }
+  }
+
+  if (!regex.module.test(content)) {
+    return { code };
+  }  
+
+  const styles = content.match(regex.style);
+  let parsedStyles = null;
+
+  let parsedSource = content.replace(regex.module, (match, className) => {
+    let replacement = '';
+
+    if (styles.length) {
+      const classRegex = new RegExp(`\\.(${className})\\b(?![-_])`, 'gm');
+      const toBeParsed = parsedStyles ? parsedStyles : styles[0];
+
+      if (classRegex.test(toBeParsed)) {
+        const interpolatedName = generateName(
+          filename,
+          styles[0],
+          className
+        );
+        parsedStyles = toBeParsed.replace(
+          classRegex,
+          () => `:global(.${interpolatedName})`
+        );
+        replacement = interpolatedName;
+      }
+    }
+    return replacement;
+  });
+
+  if (parsedStyles) {
+    parsedSource = parsedSource.replace(regex.style, parsedStyles);
+  }
+
+  return {
+    code: parsedSource
+  }
+};
+
+export default (options) => {
+  for (const option in options) {
+    pluginOptions[option] = options[option];
+  }
+  return {
+    markup,
+  }
+};

package.json

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+{
+  "name": "svelte-preprocess-cssmodules",
+  "version": "0.1.0",
+  "description": "Svelte preprocess to generate CSS Modules classname on Svelte components",
+  "keywords": [
+    "svelte",
+    "svelte-preprocess",
+    "css-modules"
+  ],
+  "homepage": "https://github.com/micantoine/svelte-preprocess-cssmodules",
+  "bugs": {
+    "url": "https://github.com/micantoine/svelte-preprocess-cssmodules/issues"
+  },
+  "author": {
+    "name": "micantoine"
+  },
+  "license": "MIT",
+  "main": "index.js",
+  "directories": {
+    "example": "example"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/micantoine/svelte-preprocess-cssmodules.git"
+  },
+  "dependencies": {
+    "loader-utils": "^1.1.0"
+  },
+  "peerDependencies": {
+    "svelte": ">1.44.0"
+  },
+  "files": [
+    "index.js"
+  ]
+}