eslint-plugin-smarter-tabs
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A tiny ESLint plugin to enforce the usage of smart tabs.
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# 🎓 eslint-plugin-smarter-tabs
[](https://coveralls.io/github/cheap-glitch/eslint-plugin-smarter-tabs?branch=main)
This plugin aims to enforce the usage of smart tabs, as defined
[in the emacs wiki](https://www.emacswiki.org/emacs/SmartTabs):
> 1. Tabs are only used at the beginning of lines. Everything else, like ASCII
> art and tables, should be formatted with spaces.
> 2. Tabs are only used for expressing the indentation level. One tab per
> “block” — any remaining whitespace is spaces only.
To accomplish this, the plugin exports a single rule which issues a report in three cases:
1. The line contains an inline tabulation:
<table>
<tr>
<th>Valid</th>
<th>Invalid</th>
</tr>
<tr>
<td>
```javascript
const foo = true;
const foobar = false;
```
</td>
<td>
```javascript
const foo———𝈷= true;
const foobar = false;
```
</td>
</tr>
</table>
2. The line use spaces for indentation. This happens when a line is indented with
spaces or starts with tabs followed by spaces, and its indentation level is
different than the one of its block:
<table>
<tr>
<th>Valid</th>
<th>Invalid</th>
</tr>
<tr>
<td>
```javascript
function foo(bar) {
————𝈷return (bar === undefined)
————𝈷 ? 'foo';
————𝈷 : 'bar';
}
```
</td>
<td>
```javascript
function foo(bar) {
————𝈷return (bar === undefined)
————𝈷————𝈷 ? 'foo';
————𝈷————𝈷 : 'bar';
}
```
</td>
</tr>
</table>
3. The line has a mismatched indentation level. This happens when the
indentation level of the line is greater than the one of the line before it by
two or more:
<table>
<tr>
<th>Valid</th>
<th>Invalid</th>
</tr>
<tr>
<td>
```javascript
if (baz) {
————𝈷let p = { x: 1,
————𝈷 y: 2,
————𝈷 z: 3,
————𝈷};
}
```
</td>
<td>
```javascript
if (baz) {
————𝈷let p = { x: 1,
————𝈷————𝈷————𝈷y: 2,
————𝈷————𝈷————𝈷z: 3,
————𝈷};
}
```
</td>
</tr>
</table>
## Installation
```shell
npm i -D eslint-plugin-smarter-tabs
```
## Usage
This plugin exports a single rule called `smarter-tabs` that you can use in your
`.eslintrc.json` or `eslintrc.js`:
```json
{
"plugins": [
"smarter-tabs"
],
"rules": {
"smarter-tabs/smarter-tabs": "warn"
}
}
```
If you use the `eslint:recommended` preset, you may also want to disable the
`no-mixed-spaces-and-tabs` rule as it might clash with this plugin:
```json
{
"rules": {
"no-mixed-spaces-and-tabs": "off",
"smarter-tabs/smarter-tabs": "warn"
}
}
```
Or you could pass it the `smart-tabs` options:
```json
{
"rules": {
"no-mixed-spaces-and-tabs": ["warn", "smart-tabs"],
"smarter-tabs/smarter-tabs": "warn"
}
}
```
## Changelog
See the full changelog [here](https://github.com/cheap-glitch/eslint-plugin-smarter-tabs/releases).
## License
This software is distributed under the ISC license.