2b:null 2c:["$","title",null,{"children":"ECMAScript 6+ (2015-2022) | Robert Batty | Observable"}] 31:[] 2f:{"id":"39b098d4e8cc5ede","slug":"ecmascript-2015-2022","title":"ECMAScript 6+ (2015-2022)","thumbnail":"ce730c113bbd5a119b2966bfa3bb929af6b0184db1a3008a0a7efe13cb0d9dde","access_level":"public","create_time":"$D2022-08-25T20:18:12.197Z","update_time":"$D2022-09-14T15:29:26.758Z","view_time":null,"first_public_time":"$D2022-08-27T05:08:15.086Z","fork":false,"stars":4,"starred":false,"owner":{"type":"team","id":"b6221ba902bfc582","login":"robertbatty","name":"Robert Batty","avatar_url":"https://avatars-next.observableusercontent.com/9e1a94f97db2169519ef196abb770ca7706e7b9c1f754526607a1f879f0dacb6","tier":"starter_2024"},"version":573,"publish_version":573,"role":null,"authored":false,"authors":[{"type":"individual","id":"659e066240c21c78","login":"robertbatty","name":"Robert Batty","avatar_url":"https://avatars-next.observableusercontent.com/9e1a94f97db2169519ef196abb770ca7706e7b9c1f754526607a1f879f0dacb6","tier":null}],"members":[{"type":"individual","id":"659e066240c21c78","login":"robertbatty","name":"Robert Batty","avatar_url":"https://avatars-next.observableusercontent.com/9e1a94f97db2169519ef196abb770ca7706e7b9c1f754526607a1f879f0dacb6","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":true,"trashed":false,"subscribed":null,"forks":1,"collection":{"id":"055b25992b60b271","slug":"docs-articles","title":"Docs, Articles","owner":{"id":"b6221ba902bfc582","login":"robertbatty","name":"Robert Batty"}},"type":"notebook","body":{"title":"ECMAScript 6+ (2015-2022)","cells":[{"id":0,"value":"# ECMAScript 6+ (2015-2022)\n\nFeatures from ECMAScript, My Highlights by Year","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":540,"value":"toc({ ignoreFirst: true })","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":274,"value":"# ES6 (2015)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":479,"value":"Features:\n\n- Functions\n - Default Params (Function)\n - Template Literals\n- Objects\n - Spread Syntax (Spread Operator for `Array`)\n - Destructuring\n - Object Assing\n- Let & Const\n- Modules & Generators\n","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":423,"value":"### Template Literals","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":425,"value":"{\n const a = 5;\n const b = 10;\n return `Fifteen is ${a + b} and not ${2 * a + b}.`;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":334,"value":"### Object Assing\n~~~~ts\nObject.assing(Object, Object): Object\n~~~~","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":9,"value":"Object.assign({ a: 1, b: 41 }, { a: 2, c: 30 })","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":516,"value":"### Spread Syntax (Array)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":572,"value":"Spread syntax (...) allows an iterable, such as an array or string, to be expanded in places where zero or more arguments (for function calls) or elements (for array literals) are expected.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":565,"value":"...","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":272,"value":"# ES7 (2016)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":487,"value":"Features:\n- Exponential Operator\n- Includes","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":15,"value":"### Exponential Operator","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":4,"value":"123 ** 2","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":339,"value":"### Includes\n~~~~ts\nArray.includes(any): Boolean\n~~~~","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":295,"value":"{\n const list = [\"oscar\", \"David\", \"Ana\"];\n // case sensible\n return list.includes(\"Oscar\"); // false\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":298,"value":"{\n let numbers = [1, 3, 4, 6, 7, 8];\n return numbers.includes(7); // true\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":270,"value":"# ES8 (2017)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":483,"value":"Features:\n- Objects:\n - Object Entries\n - Object Keys\n - Object Values\n- Async / Await\n- Trailing Commas","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":362,"value":"obj = ({\n a: \"somestring\",\n b: 42\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":438,"value":"### Async / Await","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":440,"value":"{\n async function f() {\n return Promise.resolve(1);\n }\n\n return await f();\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":343,"value":"### Object Entries\n~~~~ts\nObject.entries(Object): [string, any][] // [ ['key', value], ['key', value], ...]\n~~~~","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":352,"value":"Object.entries(obj)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":373,"value":"### Object Keys\n~~~~ts\nObject.keys(Object): string[] // [ 'key', 'key', ...]\n~~~~","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":375,"value":"Object.keys(obj)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":371,"value":"### Object Values\n~~~~js\nObject.values(obj): any[] // [value, value, ...]\n~~~~","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":359,"value":"Object.values(obj)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":452,"value":"### Trailing Commas\n\n~~~~ts\nconst arr = [\n 1,\n 2,\n 3, // comma at the end, with no error\n];\n\narr; // [1, 2, 3]\narr.length; // 3\n~~~~","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":155,"value":"# ES9 (2018)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":512,"value":"Features:\n- Rest Operator","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":202,"value":"### Rest Operator\n\n","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":198,"value":"{\n /* Operador de reposo / Rest Operator */\n const obj = {\n name: \"santiago\",\n age: 19,\n country: \"CO\"\n };\n\n let { name, ...all } = obj;\n return name, all; // santiago { age: 19, country: 'CO' }\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":262,"value":"# ES10 (2019)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":494,"value":"Features:\n- From Entries\n- Trim","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":222,"value":"### From Entries\n~~~~ts\nObject.fromEntries(map): Object\n~~~~","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":220,"value":"{\n const map = new Map([\n [\"a\", 1],\n [\"b\", 2],\n [\"c\", 3]\n ]);\n const obj = Object.fromEntries(map);\n\n return obj;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":442,"value":"### Trim\n\n~~~~ts\nString.trim(): string\nString.trimStart(): string\nString.trimEnd(): string\n~~~~ ","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":449,"value":"{\n const saludo = \" hola \";\n const result1 = saludo.trim();\n const result2 = saludo.trimStart();\n const result3 = saludo.trimEnd();\n\n return {\n result1,\n result2,\n result3\n };\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":264,"value":"# ES11 (2020)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":499,"value":"Features:\n- Optional Chaining\n- [BigInt](###BigInt)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":409,"value":"### Optional Chaining\n\n~~~~js\nobj?.prop // optional static property access\nobj?.[expr] // optional dynamic property access\nfunc?.(...args) // optional function or method call\n~~~~","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":412,"value":"{\n const adventurer = {\n name: \"Alice\",\n cat: {\n name: \"Dinah\"\n }\n };\n\n const dogName = adventurer.dog?.name;\n dogName;\n // expected output: undefined\n\n adventurer.someNonExistentMethod?.();\n // expected output: undefined\n\n return adventurer?.cat;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":462,"value":"### BigInt","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":527,"value":"> [MDN Docs](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":464,"value":"{\n const previousMaxSafe = BigInt(Number.MAX_SAFE_INTEGER);\n // ↪ 9007199254740991n\n\n const maxPlusOne = previousMaxSafe + 1n;\n // ↪ 9007199254740992n\n\n const theFuture = previousMaxSafe + 2n;\n // ↪ 9007199254740993n, this works now!\n\n const multi = previousMaxSafe * 2n;\n // ↪ 18014398509481982n\n\n const subtr = multi - 10n;\n // ↪ 18014398509481972n\n\n const mod = multi % 10n;\n // ↪ 2n\n\n const bigN = 2n ** 54n;\n // ↪ 18014398509481984n\n\n return bigN * -1n;\n // ↪ -18014398509481984n\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":266,"value":"# ES12 (2021)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":501,"value":"Features:\n- Logical Assignment Operators","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":396,"value":"### Logical Assignment Operators\n\n","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":305,"value":"{\n let [a, b] = [null, 4];\n // \"Or Or Equals\" (or, the Mallet operator :wink:)\n // a || (a = b);\n return [(a ||= b), (b ||= a)];\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":313,"value":"{\n let [a, b] = [true, 4];\n // \"And And Equals\"\n // a && (a = b);\n return (a &&= b);\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":318,"value":"{\n let [a, b] = [2, 4];\n // \"QQ Equals\"\n // a ?? (a = b);\n return (a ??= b);\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":105,"value":"# ES13 (2022)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":503,"value":"Features:\n- Array\n - At\n - Find Last\n- Top level `await`","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":149,"value":"### At\n~~~~js\nArray.at(index): any\n~~~~","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":110,"value":"[\"apple\", \"orange\", \"strawberry\"].at(0)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":124,"value":"### Top level `await`\n\nTop-level await enables modules to act as big async functions: With top-level await, ECMAScript Modules (ESM) can await resources, causing other modules who import them to wait before they start evaluating their body.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":116,"value":"{\n const response = await fetch(\"https://api.escuelajs.co/api/v1/products\");\n const products = await response.json();\n\n return { products };\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":167,"value":"### Find Last\n\nFind Last / Find Last Index\n\n~~~~ts\nArray.findLast((item) => Boolean): any\n\nArray.findLastIndex((item) => Boolean): number\n~~~~\n","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":169,"value":"{\n const array = [{ value: 1 }, { value: 2 }, { value: 3 }, { value: 4 }];\n\n array.find((n) => n.value % 2 === 1); // { value: 1 }\n array.findIndex((n) => n.value % 2 === 1); // 0\n\n // ======== Before the proposal ===========\n\n // find\n [...array].reverse().find((n) => n.value % 2 === 1); // { value: 3 }\n\n // findIndex\n array.length - 1 - [...array].reverse().findIndex((n) => n.value % 2 === 1); // 2\n array.length - 1 - [...array].reverse().findIndex((n) => n.value === 42); // should be -1, but 4\n\n // ======== In the proposal ===========\n // find\n return array.findLast((n) => n.value % 2 === 1); // { value: 3 }\n\n // findIndex\n array.findLastIndex((n) => n.value % 2 === 1); // 2\n array.findLastIndex((n) => n.value === 42); // -1\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":68,"value":"signature","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":158,"value":"Biblography\n\n- ECMAScript: Versiones de JavaScript (by Luis Ariza) (Spanish/Español)\n- TC39: Finished Proposals\n- ES6: Features\n- MDN Docs","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":63,"value":"import { signature } from \"@robertbatty/signature\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":532,"value":"import { toc } from \"@robertbatty/toc\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"}],"files":"$W31","stdlib":"1","titling":"auto"}} 30:"$2f:body"