Add “babel-preset-react” npm install babel-preset-react and add “presets” option to babel-loader in your webpack.config.js (or you can add it to your .babelrc or package.js: http://babeljs.io/docs/usage/babelrc/) Here is an example webpack.config.js: { test: /\.jsx?$/, // Match both .js and .jsx files exclude: /node_modules/, loader: “babel”, query: { presets:[‘react’] } } Recently Babel 6 was released and … Read more
If you want CommonJS export behavior, you’ll need to use CommonJS directly (or use the plugin in the other answer). This behavior was removed because it caused confusion and lead to invalid ES6 semantics, which some people had relied on e.g. export default { a: ‘foo’ }; and then import {a} from ‘./foo’; which is … Read more
Babel is a transformation framework. Pre-6.x, it enabled certain transformations by default, but with the increased usage of Node versions which natively support many ES6 features, it has become much more important that things be configurable. By default, Babel 6.x does not perform any transformations. You need to tell it what transformations to run: npm … Read more
You can await on Promise.all(): await Promise.all([someCall(), anotherCall()]); To store the results: let [someResult, anotherResult] = await Promise.all([someCall(), anotherCall()]); Note that Promise.all fails fast, which means that as soon as one of the promises supplied to it rejects, then the entire thing rejects. const happy = (v, ms) => new Promise((resolve) => setTimeout(() => resolve(v), … Read more
babel-polyfill (deprecated as of Babel 7.4) is required. You must also install it in order to get async/await working. npm i -D babel-core babel-polyfill babel-preset-es2015 babel-preset-stage-0 babel-loader package.json “devDependencies”: { “babel-core”: “^6.0.20”, “babel-polyfill”: “^6.0.16”, “babel-preset-es2015”: “^6.0.15”, “babel-preset-stage-0”: “^6.0.15” } .babelrc { “presets”: [ “es2015”, “stage-0” ] } .js with async/await (sample code) “use strict”; export … Read more
(0, _b.a)() ensures that the function _b.a is called with this set to the global object (or if strict mode is enabled, to undefined). If you were to call _b.a() directly, then _b.a is called with this set to _b. (0, _b.a)(); is equivalent to 0; // Ignore result var tmp = _b.a; tmp(); (the … Read more
Update Since Node v12 (April 2019), support for ES modules is enabled by default, and since Node v15 (October 2020) it’s stable (see here). Files including node modules must either end in .mjs or the nearest package.json file must contain “type”: “module”. The Node documentation has a ton more information, also about interop between CommonJS … Read more
Update (2022-01-13): Seems people are still finding this, here’s the current story: Optional Chaining is in the specification now (ES2020) and supported by all modern browsers, more in the archived proposal: https://github.com/tc39/proposal-optional-chaining babel-preset-env: If you need to support older environments that don’t have it, this is probably what you want https://babeljs.io/docs/en/babel-preset-env Babel v7 Plugin: https://babeljs.io/docs/en/babel-plugin-proposal-optional-chaining … Read more
this.changeContent needs to be bound to the component instance via this.changeContent.bind(this) before being passed as the onChange prop, otherwise the this variable in the body of the function will not refer to the component instance but to window. See Function::bind. When using React.createClass instead of ES6 classes, every non-lifecycle method defined on a component is … Read more