init

Author: randallmlough

.github/workflows/test.yml

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+name: CI
+on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install modules
+      run: yarn
+    - name: Run tests
+      run: yarn test

.gitignore

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+.vscode
+.DS_Store
+node_modules

babel.config.js

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+module.exports = {
+  presets: [
+    [
+      "@babel/preset-env",
+      {
+        targets: {
+          node: "current",
+        },
+      },
+    ],
+  ],
+};

index.js

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+const userAgent = () =>
+  ((navigator && navigator.userAgent) || "").toLowerCase();
+const vendor = () => ((navigator && navigator.vendor) || "").toLowerCase();
+
+const comparator = {
+  "<": (a, b) => a < b,
+  "<=": (a, b) => a <= b,
+  ">": (a, b) => a > b,
+  ">=": (a, b) => a >= b,
+};
+
+function compareVersion(version, range) {
+  let string = range + "";
+  let n = +(string.match(/\d+/) || NaN);
+  let op = string.match(/^[<>]=?|/)[0];
+  return comparator[op] ? comparator[op](version, n) : version == n || n !== n;
+}
+
+export let supportedBrowsers = {
+  msie: "none", //ie / internet explorer
+  edge: ">1", // example version range for now
+  chrome: "any",
+  firefox: "any",
+  opera: "none",
+};
+
+function isSupported(browsers = supportedBrowsers) {
+  let browser = getBrowser();
+  let version = browsers[browser];
+  if (!version || version == "none") return false;
+  if (version == "any") return true;
+  switch (browser) {
+    case "msie":
+      return isIe(version);
+    case "edge":
+      return isEdge(version);
+    case "firefox":
+      return isFirefox(version);
+    case "chrome":
+      return isChrome(version);
+  }
+}
+
+const browsersRegex = new RegExp(Object.keys(supportedBrowsers).join("|"));
+
+function getBrowser() {
+  let match = userAgent().match(browsersRegex);
+  if (!match) return null;
+  return match[0];
+}
+// can take a number or a string. Can also take a string prefixed with a comparable like, > or >=
+// example, chrome('>=90')
+function isChrome(range) {
+  let match = /google inc/.test(vendor())
+    ? userAgent().match(/(?:chrome|crios)\/(\d+)/)
+    : null;
+  return match !== null && compareVersion(match[1], range);
+}
+
+function isIe(range) {
+  let match = userAgent().match(/(?:msie |trident.+?; rv:)(\d+)/);
+  return match !== null && compareVersion(match[1], range);
+}
+
+function isEdge(range) {
+  let match = userAgent().match(/edge\/(\d+)/);
+  return match !== null && compareVersion(match[1], range);
+}
+
+function isFirefox(range) {
+  let match = userAgent().match(/(?:firefox|fxios)\/(\d+)/);
+  return match !== null && compareVersion(match[1], range);
+}
+
+export default {
+  supportedBrowsers,
+  compareVersion,
+  isSupported,
+  isChrome,
+  isIe,
+  isEdge,
+  isFirefox,
+};

package.json

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+{
+  "name": "is-supported",
+  "version": "1.0.0",
+  "description": "determines if client is running on a supported browser",
+  "main": "index.js",
+  "scripts": {
+    "test": "jest --runInBand --forceExit"
+  },
+  "author": "Randy Lough",
+  "license": "ISC",
+  "devDependencies": {
+    "@babel/core": "^7.14.3",
+    "@babel/preset-env": "^7.14.2",
+    "babel-jest": "^26.6.3",
+    "jest": "^26.6.3"
+  }
+}