gremlint/README.md

Linter/code formatter for Gremlin

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![Gremlint Github Header 1920x1024](https://user-images.githubusercontent.com/25663729/88488788-d5a73700-cf8f-11ea-9adb-03d62c77c1b7.png)

### What is Gremlint?

Gremlint is a code formatter, from [Apache TinkerPop™][tk] which parses Gremlin queries and rewrites them to adhere to certain styling rules. It does so by parsing the query to an abstract syntax tree, and reprinting it from scratch.

### But why?

- To make Gremlin queries more readable
- To make your queries more beautiful
- To act as a "living" style guide

### Install Gremlint as a JavaScript / TypeScript package

```bash
npm install gremlint
```

### Basic example

```typescript
import { formatQuery } from 'gremlint';

const unformattedQuery = `g.V().has('person', 'name', 'marko').shortestPath().with(ShortestPath.target, __.has('name', 'josh')).with(ShortestPath.distance, 'weight')`;

const formattedQuery = formatQuery(unformattedQuery);

console.log(formattedQuery);
```

```
g.V().
  has('person', 'name', 'marko').
  shortestPath().
    with(ShortestPath.target, __.has('name', 'josh')).
    with(ShortestPath.distance, 'weight')
```

### Override default max line length

The default max line length is 80, but it can easily be overridden.

```typescript
import { formatQuery } from 'gremlint';

const unformattedQuery = `g.V().has('person', 'name', 'marko').shortestPath().with(ShortestPath.target, __.has('name', 'josh')).with(ShortestPath.distance, 'weight')`;

const formattedQuery = formatQuery(unformattedQuery, { maxLineLength: 50 });

console.log(formattedQuery);
```

```
g.V().
  has('person', 'name', 'marko').
  shortestPath().
    with(
      ShortestPath.target,
      __.has('name', 'josh')).
    with(ShortestPath.distance, 'weight')
```

### Other formatting options

```typescript
import { formatQuery } from 'gremlint';

const unformattedQuery = `g.V().has('person', 'name', 'marko').shortestPath().with(ShortestPath.target, __.has('name', 'josh')).with(ShortestPath.distance, 'weight')`;

const formattedQuery = formatQuery(unformattedQuery, {
  indentation: 4, // default: 0
  maxLineLength: 40, // default: 80
  shouldPlaceDotsAfterLineBreaks: true, // default: false
});

console.log(formattedQuery);
```

```
    g.V()
      .has('person', 'name', 'marko')
      .shortestPath()
        .with(
          ShortestPath.target,
          __.has('name', 'josh'))
        .with(
          ShortestPath.distance,
          'weight')
```

### Just looking for an online Gremlin query formatter?

https://gremlint.com is a website which utilizes the Gremlint library to give users an online "living" style guide for Gremlin queries. It also serves as a platform for showcasing the features of Gremlint. Its source code is available [here](https://github.com/apache/tinkerpop/tree/master/docs/site/home/gremlint).
![Gremlint V2 Screenshot](https://user-images.githubusercontent.com/25663729/88488518-f078ac00-cf8d-11ea-9e1c-01edec285751.png)

[tk]: https://tinkerpop.apache.org