Arrow function “expression expected” syntax error
I had the error expression expected reported by Webstorm when editing a Node.js program. In this case the solution is to set the language version to a version that supports this feature.
ecmascript-6
How can I turn off ESLint’s no-restricted-syntax rule just for ForOfStatement?
Check existing config Based on the current master branch, eslint-config-airbnb currently disables four syntax forms: ForInStatement ForOfStatement LabeledStatement WithStatement You can verify this or see if there are any differences by using ESLint’s –print-config CLI flag: $ eslint –print-config file.js ESLint will print out the config it would use to lint file.js, and you can … Read more
Is it safe to use async/await now? [closed]
There are two places I check whenever I have questions such as this: The Can I Use website: http://caniuse.com/#search=await And Node Green: http://node.green/#async-functions Typically an answer is encouraged to include the relevant information to avoid link rot. But ironically this answer has exactly the opposite problem: this answer will rot (the information below will become … Read more
useSelector not updating when store has changed in Reducer. ReactJS Redux
NOTE: you better start using redux-toolkit to prevent references in you code its a better and almost a must way for using redux the problem your facing is very common when handling with objects, the props do not change because you’re changing an object property but the object itself does not change from the react … Read more
How to handle eslint no-param-reassign rule in Array.prototype.reduce() functions
I just wrap the reduce functions in a lint rule disable block, ie: /* eslint-disable no-param-reassign */ const newObject = [‘a’, ‘b’, ‘c’].reduce((result, item, index) => { result[item] = index; return result; }, {}); /* eslint-enable no-param-reassign */
What do curly braces mean in JSX (React)?
The curly braces are a special syntax to let the JSX parser know that it needs to interpret the contents in between them as JavaScript instead of a string. You need them when you want to use a JavaScript expression like a variable or a reference inside JSX. Because if you use the standard double … Read more
How to minify ES6 code using Webpack?
Not sure if you’re still looking for an answer to this, but now you can include the beta version of uglifyjs-webpack-plugin as a webpack plugin and it’ll use uglify-es which can minify ES6 code. npm install uglifyjs-webpack-plugin and then in your webpack.config.js: const Uglify = require(“uglifyjs-webpack-plugin”); module.exports = { entry: …, output: …, plugins: [ … Read more
Add elements inside Array conditionally in JavaScript
When you spread into an array, you call the Symbol.iterator method on the object. && evaluates to the first falsey value (or the last truthy value, if all are truthy), so let arr2 = [‘value2’, …(condition && arr)]; results in let arr2 = [‘value2’, …(false)]; But false does not have a Symbol.iterator method. You could … Read more
Using ES6 Classes as Angular 1.x directives
From my point of view, there is no need to use external libraries like register.js, because you can create directive as a ES6 class in this way: class MessagesDirective { constructor() { this.restrict=”E” this.templateUrl=”messages.html” this.scope = {} } controller($scope, $state, MessagesService) { $scope.state = $state; $scope.service = MessagesService; } link(scope, element, attrs) { console.log(‘state’, scope.state) … Read more