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ECMAScript
ECMAScript: A language standardized by ECMA International.
JavaScript: The commonly used name for implementations of the ECMAScript standard.
ECMAScript 5 (ES5): The 5th edition of ECMAScript, standardized in 2009. This standard has
been implemented fairly completely in all modern browsers
ECMAScript 6 (ES6)/ ECMAScript 2015 (ES2015): The 6th edition of ECMAScript, standardized
in 2015. This standard has been partially implemented in most modern browsers. To see the
state of implementation by different browsers and tools, check out these compatibility tables.
ECMAScript 7 / 2016
ECMAScript 8 / 2017
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Polyfills & transpiling
“A polyfill, or polyfiller, is a piece of code (or plugin) that provides the technology that you, the
developer, expect the browser to provide natively. Flattening the API landscape if you will.”
https://remysharp.com/2010/10/08/what-is-a-polyfill
“A transpiler takes the syntax that older browsers won’t understand (e.g. classes, ‘const’, arrow
functions), and turns them into syntax they will understand (functions, ‘var’, functions).”
https://hackernoon.com/polyfills-everything-you-ever-wanted-to-know-or-maybe-a-bit-less-
7c8de164e423
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ES6 new features
• Constants, let
• Default arguments
• String interpolation
• Property shorthands
• Spread operators
• Object & array destructuring
• Arrow functions (lambda expressions)
• Promises
• Classes & class inheritance
All features - http://es6-features.org
https://egghead.io/courses/learn-es6-ecmascript-2015
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Modules
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• JavaScript Modules refer to a small units of independent, reusable code
• They seems to mimic how classes are used in Java or Python.
https://medium.com/sungthecoder/javascript-module-module-loader-module-bundler-es6-module-
confused-yet-6343510e7bde
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https://webpack.js.org/concepts/
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• npm init
• npm install
• npm run …
https://docs.npmjs.com/getting-started/what-is-npm
Maintainable code
Code analysis
A linter or lint refers to tools that analyze source code to flag programming errors, bugs, stylistic
errors, and suspicious constructs.
• Eslint, JSLint, JSHint
Lack of static typing
Static typed languages are those in which type checking is done at compile-time, whereas
dynamic typed languages are those in which type checking is done at run-time.
• Typescript, Flow
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Maintainable styles
BEM
Methodology that helps you to create reusable components. Core concept is to create the
styles for components based on Block (standalone meaningful entity), Element (part
semantically tied to its block), Modifier (appearance or behavior flag).
LESS
Backwards-compatible language extension for CSS. LESS looks just like CSS, it only makes a few
convenient additions. Among them are variables, nesting, operations, functions and much more.
• {less}
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https://github.com/facebook/create-react-app