Develop Reference

Align JavaScript imports "from" Statement to be Vertically Aligned

I would like the end result of my imports to be like this, via a tool that can automatically format my code onSave:
import { Stack, StackProps, Duration, Resource } from "aws-cdk-lib";
import { LambdaStack } from "./lambda-Stack";
import { Construct } from "constructs";
How can I align all of the "from" statements vertically in VS Code? I've looked at both prettier and eslint.

Prettier doesn't care what you want. :-) It's an opinionated tool useful for applying consistency to code within teams (and for avoiding arguments about different formatting styles [although you just get arguments about whether to use Prettier instead]).
If you don't want Prettier's formatting, don't use Prettier. There are other code formatters, some of which offer more control than Prettier does.
You could tell Prettier to ignore each of those import statements:
// prettier-ignore
import { Stack, StackProps, Duration, Resource } from "aws-cdk-lib";
// prettier-ignore
import { LambdaStack } from "./lambda-Stack";
// prettier-ignore
import { Construct } from "constructs";
or
/* prettier-ignore*/ import { Stack, StackProps, Duration, Resource } from "aws-cdk-lib";
/* prettier-ignore*/ import { LambdaStack } from "./lambda-Stack";
/* prettier-ignore*/ import { Construct } from "constructs";
For now there's no "block ignore" in Prettier for JavaScript (only for certain select other languages), although there's an open request for one.

Usually, with prettier or eslint you might want to limit printWidth to defined number of caracter per line. So imagine if you have many imports or long module name :
/* You better should break line overhere |----------| */
import { DepA, DepB, DepC, DepD, DepE, DepF, DepG, DepH, DepI, DepJ } from "./some-long-named-module";
import { OnlyOneImport } from "./other-module";
So my answer is not responding to "how can you align 'from' statements?" but it
may open another question 'should you ?'
Here is a common way to indent imports :
// common way to write import with vertical (Automatable)
import {
DepA,
DepB,
DepC,
DepD,
DepE,
DepF,
DepG,
DepH,
DepI,
DepJ
} from "./some-long-named-module";
import { OnlyOneImport } from "./other-module";
Here is the eslint rule to auto indent your code : https://eslint.org/docs/latest/rules/object-curly-newline
example for object-curly-newline rule in eslint:
# .estlintrc.json
{
...
"rules": {
...
"object-curly-newline": [
"error",
{
"consistent": true,
"multiline": true
}
]
}
}
PS:
Here some example of how I use it
# .estlintrc.json
{
"root": true,
"extends": [
"airbnb-base", // See https://www.npmjs.com/package/eslint-config-airbnb
"airbnb-base/whitespace",
"plugin:jest/recommended", // See https://www.npmjs.com/package/eslint-plugin-jest
"prettier" // See https://github.com/prettier/eslint-config-prettier
],
"env": {
"jest/globals": true
},
"plugins": [
"jest",
"...whatever-you-want"
],
"ignorePatterns": [
"dist/",
"node_modules/",
"...whatever-you-want"
],
"rules": {
"no-restricted-syntax": [
"error",
"WithStatement",
"BinaryExpression[operator='in']"
],
"no-console": [
0,
{
"allow": [
"info",
"warn",
"error"
]
}
],
"quotes": [
"error",
"single",
"avoid-escape"
],
"object-curly-newline": [
"error",
{
"consistent": true,
"multiline": true
}
],
"...whatever-you-want"
}
}
# .prettierrc
{
"printWidth": 80,
"trailingComma": "es5",
"useTabs": false,
"tabWidth": 2,
"semi": true,
"singleQuote": true,
"quoteProps": "as-needed",
"jsxSingleQuote": false,
"bracketSpacing": true,
"bracketSameLine": false,
"proseWrap": "preserve",
"arrowParens": "avoid",
"endOfLine": "lf",
"parser": "babel"
}

Error when enabling react/jsx-sort-props [Rules of eslint-plugin-react]

I`m trying to sort props names alphabetically in my project using the plugin eslint-plugin-react.
I've read the jsx-sort-props rules option example and I'm here asking myself: What's props should be used in the <enable> field?
...
"react/jsx-sort-props": [<enabled>, {
"callbacksLast": <boolean>,
"shorthandFirst": <boolean>,
"shorthandLast": <boolean>,
"multiline": "ignore" | "first" | "last",
"ignoreCase": <boolean>,
"noSortAlphabetically": <boolean>,
"reservedFirst": <boolean>|<array<string>>,
}]
...
I've tried everything but always get an invalid configuration notification:
*Error: ESLint configuration in .eslintrc.JSON is invalid: Unexpected top-level property "react/jsx-sort-props".*
I'm editing it at my .eslintrc.json file:
{
"extends": [
"eslint:recommended",
"plugin:react/recommended",
"next/core-web-vitals"
],
"react/jsx-sort-props": [<enabled>, {
"callbacksLast": true,
"shorthandFirst": false,
"shorthandLast": true,
"multiline": "last",
"ignoreCase": true,
"noSortAlphabetically": false,
"reservedFirst": false
}]
}

You need to put your rules into the rules property of the object, not into the top level of the object:
{
"extends": [
"eslint:recommended",
"plugin:react/recommended",
"next/core-web-vitals"
],
"rules": {
"react/jsx-sort-props": [<enabled>, {
This helps clearly delimit the difference between ESLint configuration settings and rules - otherwise, the overlap would be confusing, and if there were ever a rule whose name conflicted with a possible other top-level property, there'd be problems.

eslint no-use-before-define rules does not work in node.js

I use node.js 12.3.0 and i had installed eslint 7.0.0 by npm.
So i wrote the .eslintrc.js like below.
module.exports = {
"env": {
"commonjs": true,
"es6": true,
"node": true
},
"globals": {
"Atomics": "readonly",
"SharedArrayBuffer": "readonly"
},
"parserOptions": {
"ecmaVersion": 12
},
"rules": {
"semi": ["error", "always", {"omitLastInOneLineBlock": true }],
"no-shadow-restricted-names" : "error",
"no-unused-vars": ["warn", { "vars": "all" }],
"no-redeclare": ["error", { "builtinGlobals": true }],
"no-use-before-define": ["error", { "functions": true, "classes": true, "variables": true }]
}
};
As you know, i already added "no-use-before-define" but it didn't work.
All another eslint rules are worked fine but only "no-use-before-define" didn't check anythings.
Here is my examples js file.
let c = qwertqwert(); //As you know qwerqwert is not defined. I want to check this.
a = 123123; //I don't want to allow assign any value to variable before declaration.
b = asdfafasfdasdfas; //Also i need to check any undefined variable or functions are used.
Does "no-use-before-define" can check this?
It seems only can check when i use the variable or function before define or declaration.
Func(); //I use(call) first.
//But the define statement is after.
function Func()
{
return 10;
}
Above code had checked fine by eslint but it is meaningless.
Because i want let eslint to check usage of undefined functions or value.

if you define eslint should show the error you should write a rule like
if you don't want rule you can remove it or skip rule by file
"no-use-before-define": [
"error",
{
"functions": false,
"classes": false,
"variables": false
}
],
NOTE :- i am using extension of airbnb
extends: [
'airbnb-base',
],
it works for me
node js :- 14.17.6
eslint :- 7.12.1+
and if function is not defined then it shows

no-use-before-define wrongly catches use of the global window variable

Working in electron vue-cli project. Trying to upgrade eslint but the default setup has no-use-before-define enabled.
This causes it to catch every use of things like window.process.env.username as an error.
I tried setting my rules as "no-use-before-define": ["error", { "variables": false }], but it didn't help. Adding window as a global also didn't help. Is there a way to fix eslint to be happy with the window variable?
I do like the idea of this feature, so I would like to leave it on if possible. But just turning it off is ok too if that's the best answer.
If it helps, this is my current .eslintrc.js file
// https://eslint.org/docs/user-guide/configuring
module.exports = {
root: true,
parserOptions: {
parser: 'babel-eslint'
},
env: {
browser: true
},
extends: [
// https://github.com/vuejs/eslint-plugin-vue#priority-a-essential-error-prevention
// consider switching to `plugin:vue/strongly-recommended` or `plugin:vue/recommended` for stricter rules.
'plugin:vue/essential',
// https://github.com/standard/standard/blob/master/docs/RULES-en.md
'standard'
],
// required to lint *.vue files
plugins: [
'vue'
],
// add your custom rules here
rules: {
// Don't error on variables that are global, like window, not working.
"no-use-before-define": ["error", { "variables": false }],
'generator-star-spacing': 'off',
'no-debugger': process.env.NODE_ENV === 'production' ? 'error' : 'off',
"vue/html-self-closing": ["error", {
"html": {
"void": "always",
"normal": "any",
"component": "always"
},
"svg": "always",
"math": "always"
}]
}
}
Thanks
-Edit
Tried
globals: {
window: 'writable'
},
But to no effect

ESLint: First instance of let results in "unexpected token" error [duplicate]

This question already has an answer here:
Eslint, how to accept const and arrow function in Javascript?
(1 answer)
Closed 6 years ago.
My javascript:
let foo = 'bar'
Why does ESLint respond with the following?
~/index.js
1:5 error Parsing error: Unexpected token foo
✖ 1 problem (1 error, 0 warnings)
It seems like no matter where in the script, the first instance of using let to set a variable gets this error. Why??
My .eslintrc file:
module.exports = {
"env": {
"node": true
},
"extends": "eslint:recommended",
"rules": {
"indent": [
"error",
"tab"
],
"linebreak-style": [
"error",
"unix"
],
"quotes": [
"error",
"single"
],
"semi": [
"error",
"never"
]
}
};

The answers about let being forbidden in the global scope are wrong. That's fine.
The problem is that you need to let eslint know you're using es6 features.
Do that by adding an "es6": true line to the env block in your config:
.eslintrc.js
module.exports = {
"env": {
"node": true,
"es6": true
},
"extends": "eslint:recommended",
"rules": {
"indent": [
"error",
"tab"
],
"linebreak-style": [
"error",
"unix"
],
"quotes": [
"error",
"single"
],
"semi": [
"error",
"never"
]
}
};
That fixes your particular error, but you'll soon see errors about unused names. Below is the minimum source code I could find that will pass your eslint settings:
let.js
let foo = 'bar'
function main() {
foo
}
main()

Variables declared with let are not accessible before they are declared in their enclosing block - so the first element will be undefined until the closing block is hit. If you are you defining foo in the global namespace, you will always get this error with using let in a loop.