https://github.com/estebgonza/ts-mongo-aggregation-parser

TS Parser for Mongo pipeline aggregation queries
https://github.com/estebgonza/ts-mongo-aggregation-parser

Last synced: about 17 hours ago
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TS Parser for Mongo pipeline aggregation queries

• Host: GitHub
• URL: https://github.com/estebgonza/ts-mongo-aggregation-parser
• Owner: estebgonza
• Created: 2023-03-12T21:19:19.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2024-09-09T15:04:44.000Z (24 days ago)
• Last Synced: 2024-09-09T18:27:36.384Z (24 days ago)
• Language: TypeScript
• Size: 155 KB
• Stars: 2
• Watchers: 1
• Forks: 0
• Open Issues: 7
• Metadata Files:
  • Readme: README.md

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README

        
# ts-mongo-aggregation-parser

[![Tests Status](https://github.com/estebgonza/ts-mongo-aggregation-parser/actions/workflows/tests.yaml/badge.svg)](https://github.com/estebgonza/ts-mongo-aggregation-parser/actions/workflows/tests.yaml/badge.svg)

This parser is generated using [pegjs](https://pegjs.org/). It parses a string containing a MongoDB aggregation pipeline and returns an AST.

The AST Types are defined in [src/ast-types.ts](src/ast-types.ts).

This package is compatible with CommonJS and ESM.

## Motivations

Allow [Maggregor](https://github.com/maggregor/maggregor) to parse request pipelines on MongoDB.

Maggregor is a simple data-layer that speeds up MongoDB queries: https://github.com/maggregor/maggregor

## Installation

```bash

npm install ts-mongo-aggregation-parser

yarn add ts-mongo-aggregation-parser

pnpm add ts-mongo-aggregation-parser

```

## Parser usage

```typescript

import { astTypes, parse } from 'ts-mongo-aggregation-parser'

const pipeline = `[

{

  $group: {

    _id: '$name',

    count: {

      $sum: 1,

    },

  },

},

]`

const ast = parse(pipeline)

```

## Using the AST Visitor

The Visitor AST provides a good way to traverse and manipulate our custom Abstract Syntax Trees (ASTs). To use the AST visitor, simply extend the `BaseASTVisitor` class and override the methods for the specific AST node types you're interested in. Below is a brief example:

```typescript

import {

	ASTAggregationExpression,

	ASTField,

	ASTProperty,

	ASTStageGroup,

	ASTStageList,

	ASTVisitor,

	BaseASTVisitor,

} from './ts-mongo-aggregation-parser'

class CustomASTVisitor extends BaseASTVisitor {

	visitStageGroup(stageGroup: ASTStageGroup): void {

		console.log(`StageGroup ID: ${stageGroup.id.name}`)

	}

	visitAggregationExpression(agg: ASTAggregationExpression): void {

		console.log(`Aggregation Operator: ${agg.operator}`)

	}

}

// Assuming you have created an AST

const ast = new ASTStageList() /* your stages here */

// Use your custom visitor

const visitor = new CustomASTVisitor()

ast.accept(visitor)

```

## Supported aggregation operators

- [x] $sum

- [x] $avg

- [x] $max

- [x] $min

- [ ] $push

- [ ] $addToSet

- [ ] $first

- [ ] $last

- [ ] $addToSet

## Supported stages

- [x] $group

- [ ] $project

- [ ] $match

- [ ] $limit

- [ ] $skip

- [ ] $unwind

- [ ] $sort