base on NodeJS module to create polyfill bundles tailored to individual user-agents. # Polyfill-library &middot; [![license][license-badge]][license] [![PRs Welcome][pull-requests-badge]][contributing-guide] > NodeJS module to create polyfill bundles tailored to individual user-agents ## Install ```bash npm install polyfill-library --save ``` ## Usage ```javascript const polyfillLibrary = require('polyfill-library'); const polyfillBundle = polyfillLibrary.getPolyfillString({ uaString: 'Mozilla/5.0 (Windows; U; MSIE 7.0; Windows NT 6.0; en-US)', minify: true, features: { 'es6': { flags: ['gated'] } } }).then(function(bundleString) { console.log(bundleString); }); ``` ## API ### `polyfillLibrary.listAllPolyfills()` Get a list of all the polyfills which exist within the collection of polyfill sources. Returns a Promise which resolves with an array of all the polyfills within the collection. ### `polyfillLibrary.describePolyfill(featureName)` Get the metadata for a specific polyfill within the collection of polyfill sources. - `@param {String} featureName` - The name of a polyfill whose metadata should be returned. Returns a Promise which resolves with the metadata or with `undefined` if no metadata exists for the polyfill. ### `polyfillLibrary.getOptions(opts = {})` Create an options object for use with `getPolyfills` or `getPolyfillString`. - `@param {object} opts` - Valid keys are uaString, minify, unknown, excludes, rum and features. - `@param {Boolean} [opts.minify=true]` - Whether to return the minified or raw implementation of the polyfills. - `@param {'ignore'|'polyfill'} [opts.unknown='polyfill']` - Whether to return all polyfills or no polyfills if the user-agent is unknown or unsupported. - `@param {Object} [opts.features={}]` - Which features should be returned if the user-agent does not support them natively. - `@param {Array<String>} [opts.excludes=[]]` - Which features should be excluded from the returned object. - `@param {String} [opts.uaString='']` - The user-agent string to check each feature against. - `@param {Boolean} [opts.rum=false]` - Whether to include a script that reports anonymous usage data in the polyfill bundle. Returns an object which has merged `opts` with the defaults option values. ### `polyfillLibrary.getPolyfills(opts)` Given a set of features that should be polyfilled in 'opts.features' (with flags i.e. `{<featurename>: {flags:Set[<flaglist>]}, ...}`), determine which have a configuration valid for the given opts.uaString, and return a promise of set of canonical (unaliased) features (with flags) and polyfills. - `@param {object} opts` - Valid keys are uaString, minify, unknown, excludes, rum and features. - `@param {Boolean} [opts.minify=true]` - Whether to return the minified or raw implementation of the polyfills. - `@param {'ignore'|'polyfill'} [opts.unknown='polyfill']` - Whether to return all polyfills or no polyfills if the user-agent is unknown or unsupported. - `@param {Object} [opts.features={}]` - Which features should be returned if the user-agent does not support them natively. - `@param {Array<String>} [opts.excludes=[]]` - Which features should be excluded from the returned object. - `@param {String} [opts.uaString='']` - The user-agent string to check each feature against. - `@param {Boolean} [opts.rum=false]` - Whether to include a script that reports anonymous usage data in the polyfill bundle. Returns a Promise which resolves to an Object which contains the canonicalised feature definitions filtered for UA. ### `polyfillLibrary.getPolyfillString(opts)` Create a polyfill bundle. - `@param {object} opts` - Valid keys are uaString, minify, unknown, excludes, rum and features. - `@param {Boolean} [opts.minify=true]` - Whether to return the minified or raw implementation of the polyfills. - `@param {'ignore'|'polyfill'} [opts.unknown='polyfill']` - Whether to return all polyfills or no polyfills if the user-agent is unknown or unsupported. - `@param {Object} [opts.features={}]` - Which features should be returned if the user-agent does not support them natively. - `@param {Array<String>} [opts.excludes=[]]` - Which features should be excluded from the returned object. - `@param {String} [opts.uaString='']` - The user-agent string to check each feature against. - `@param {Boolean} [opts.rum=false]` - Whether to include a script that reports anonymous usage data in the polyfill bundle. - `@param {Boolean} [opts.stream=false]` - Whether to return a stream or a string of the polyfill bundle. Returns a polyfill bundle as either a utf-8 ReadStream or as a Promise of a utf-8 String. ## AWS Lambda To use this package in an AWS Lambda function, you need to include the distribution Polyfills located in `./node_modules/polyfill-library/polyfills/__dist` in the root directory of your Lambda. In AWS, Lambdas are executed in the `/var/task/...` directory. Therefore, during execution, the directory where the polyfills will be located will be `/var/task/polyfill-library/__dist`. ### Example of a script to copy files The following snippet will allow us to copy the polyfills to our already compiled Lambda. To do this, we will first install the necessary dependencies. ```bash yarn add -D make-dir fs-extra ``` Once the dependencies are installed, we will create the file with the script at `/scripts/polyfills-serverless.mjs` and replace `YOUR_BUNDELED_LAMBDA_DIRECTORY` with the directory that contains our packaged Lambda. In the example, we will use the directory `./.serverless_nextjs/api-lambda`, which is the one used when using Serverless Next.js. ```js import { copySync } from 'fs-extra/esm'; import makeDir from 'make-dir'; const DIR_POLYFILLS = './node_modules/polyfill-library/polyfills/__dist'; // const DIR_SERVERLESS = 'YOUR_BUNDELED_LAMBDA_DIRECTORY/polyfills/__dist'; const DIR_SERVERLESS = './.serverless_nextjs/api-lambda/polyfills/__dist'; const paths = await makeDir(DIR_SERVERLESS); console.log(`The directory ${paths} is created successfully.`); try { console.log('Copying polyfills to serverless directory...'); copySync(DIR_POLYFILLS, DIR_SERVERLESS, { overwrite: false }); console.log('Polyfills copied successfully!'); } catch (err) { console.error(err); } ``` To execute the script, you will need to run the following command: ```bash node ./scripts/polyfills-serverless.mjs ``` ## Contributing Development of polyfill-library happens on GitHub. Read below to learn how you can take part in contributing to Polyfill.io. ### [Contributing Guide][contributing-guide] Read our [contributing guide][contributing-guide] to learn about our development process, how to propose bugfixes and improvements, and how to build and test your changes. ``` # To test on BrowserStack you will need to have a BrowserStack account # We test pull-requests using BrowserStack npm run test-all-polyfills # Run the tests for all polyfills using BrowserStack npm run test-polyfills -- --features=Array.from # Run the tests for Array.from npm run test-polyfills -- --features=Array.from --browserstack # Run the tests for Array.from using BrowserStack ``` ### License Polyfill-library is [MIT licensed][license]. [contributing-guide]: https://github.com/Financial-Times/polyfill-library/blob/master/.github/contributing.md [license]: https://github.com/Financial-Times/polyfill-library/blob/master/LICENSE.md [license-badge]: https://img.shields.io/badge/license-MIT-blue.svg [pull-requests-badge]: https://img.shields.io/badge/PRs-welcome-brightgreen.svg ", Assign "at most 3 tags" to the expected json: {"id":"8152","tags":[]} "only from the tags list I provide: [{"id":77,"name":"3d"},{"id":89,"name":"agent"},{"id":17,"name":"ai"},{"id":54,"name":"algorithm"},{"id":24,"name":"api"},{"id":44,"name":"authentication"},{"id":3,"name":"aws"},{"id":27,"name":"backend"},{"id":60,"name":"benchmark"},{"id":72,"name":"best-practices"},{"id":39,"name":"bitcoin"},{"id":37,"name":"blockchain"},{"id":1,"name":"blog"},{"id":45,"name":"bundler"},{"id":58,"name":"cache"},{"id":21,"name":"chat"},{"id":49,"name":"cicd"},{"id":4,"name":"cli"},{"id":64,"name":"cloud-native"},{"id":48,"name":"cms"},{"id":61,"name":"compiler"},{"id":68,"name":"containerization"},{"id":92,"name":"crm"},{"id":34,"name":"data"},{"id":47,"name":"database"},{"id":8,"name":"declarative-gui "},{"id":9,"name":"deploy-tool"},{"id":53,"name":"desktop-app"},{"id":6,"name":"dev-exp-lib"},{"id":59,"name":"dev-tool"},{"id":13,"name":"ecommerce"},{"id":26,"name":"editor"},{"id":66,"name":"emulator"},{"id":62,"name":"filesystem"},{"id":80,"name":"finance"},{"id":15,"name":"firmware"},{"id":73,"name":"for-fun"},{"id":2,"name":"framework"},{"id":11,"name":"frontend"},{"id":22,"name":"game"},{"id":81,"name":"game-engine "},{"id":23,"name":"graphql"},{"id":84,"name":"gui"},{"id":91,"name":"http"},{"id":5,"name":"http-client"},{"id":51,"name":"iac"},{"id":30,"name":"ide"},{"id":78,"name":"iot"},{"id":40,"name":"json"},{"id":83,"name":"julian"},{"id":38,"name":"k8s"},{"id":31,"name":"language"},{"id":10,"name":"learning-resource"},{"id":33,"name":"lib"},{"id":41,"name":"linter"},{"id":28,"name":"lms"},{"id":16,"name":"logging"},{"id":76,"name":"low-code"},{"id":90,"name":"message-queue"},{"id":42,"name":"mobile-app"},{"id":18,"name":"monitoring"},{"id":36,"name":"networking"},{"id":7,"name":"node-version"},{"id":55,"name":"nosql"},{"id":57,"name":"observability"},{"id":46,"name":"orm"},{"id":52,"name":"os"},{"id":14,"name":"parser"},{"id":74,"name":"react"},{"id":82,"name":"real-time"},{"id":56,"name":"robot"},{"id":65,"name":"runtime"},{"id":32,"name":"sdk"},{"id":71,"name":"search"},{"id":63,"name":"secrets"},{"id":25,"name":"security"},{"id":85,"name":"server"},{"id":86,"name":"serverless"},{"id":70,"name":"storage"},{"id":75,"name":"system-design"},{"id":79,"name":"terminal"},{"id":29,"name":"testing"},{"id":12,"name":"ui"},{"id":50,"name":"ux"},{"id":88,"name":"video"},{"id":20,"name":"web-app"},{"id":35,"name":"web-server"},{"id":43,"name":"webassembly"},{"id":69,"name":"workflow"},{"id":87,"name":"yaml"}]" returns me the "expected json"