https://github.com/idris-maps/deno-ndjson
CLI tools for dealing with ndjson in Deno
https://github.com/idris-maps/deno-ndjson
deno ndjson
Last synced: about 2 months ago
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CLI tools for dealing with ndjson in Deno
- Host: GitHub
- URL: https://github.com/idris-maps/deno-ndjson
- Owner: idris-maps
- Created: 2020-08-27T20:18:02.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2020-08-27T21:03:49.000Z (over 4 years ago)
- Last Synced: 2025-03-08T00:11:16.329Z (about 2 months ago)
- Topics: deno, ndjson
- Language: TypeScript
- Homepage:
- Size: 1.95 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
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README
# deno-ndjson
CLI tools for dealing with [ndjson](http://ndjson.org/) in [Deno](https://deno.land/). Heavily inspired by [ndjson-cli](https://github.com/mbostock/ndjson-cli) for [node](https://nodejs.org).
## `ndj-cat`
reads a `ndjson` file into the console line by line
### install
```bash
deno install --allow-read https://raw.githubusercontent.com/idris-maps/deno-ndjson/master/ndj-cat.ts
```
### usage
```bash
ndj-cat
```
#### example
```bash
ndj-cat some_folder/file.ndjson
```
## `ndj-map`
maps every line of an `ndjson`.
Takes one argument, the expression to map.
The expression assumes there are two arguments:
* `d`, the `json` line
* `i`, the index of the line
### install
```bash
deno install https://raw.githubusercontent.com/idris-maps/deno-ndjson/master/ndj-map.ts
```
### usage
```bash
ndj-map
```
#### example
Suppose you have a `file.ndjson` such as:
```
{"nom":"Lausanne","population":138905}
{"nom":"Yverdon-les-Bains","population":30143}
{"nom":"Montreux","population":26574}
{"nom":"Renens","population":21036}
{"nom":"Nyon","population":20533}
{"nom":"Vevey","population":19827}
```
```bash
ndj-cat file.ndjson \
| ndj-map '({ index: i, town: d.nom })'
```
will return
```
{"index":0,"town":"Lausanne"}
{"index":1,"town":"Yverdon-les-Bains"}
{"index":2,"town":"Montreux"}
{"index":3,"town":"Renens"}
{"index":4,"town":"Nyon"}
{"index":5,"town":"Vevey"}
```
## `ndj-filter`
filters lines of an `ndjson`.
Takes one argument, an expression that assumes two arguments:
* `d`, the `json` line
* `i`, the index of the line
### install
```bash
deno install https://raw.githubusercontent.com/idris-maps/deno-ndjson/master/ndj-filter.ts
```
### usage
```bash
ndj-filter
```
#### example
Suppose you have a `file.ndjson` such as:
```
{"nom":"Lausanne","population":138905}
{"nom":"Yverdon-les-Bains","population":30143}
{"nom":"Montreux","population":26574}
{"nom":"Renens","population":21036}
{"nom":"Nyon","population":20533}
{"nom":"Vevey","population":19827}
```
```bash
ndj-cat file.ndjson \
| ndj-filter 'd.population > 30000'
```
will return
```
{"nom":"Lausanne","population":138905}
{"nom":"Yverdon-les-Bains","population":30143}
```
## `ndj-reduce`
reduces an `ndjson`.
Takes either no arguments or two arguments.
If there are no arguments, it will return a `json` array.
If there are arguments, there must be two: the expression and the initial value. The expression assumes three arguments:
* `a`, the accumulator
* `d`, the `json` line
* `i`, the index
### install
```bash
deno install https://raw.githubusercontent.com/idris-maps/deno-ndjson/master/ndj-reduce.ts
```
### usage
```bash
ndj-reduce
## or
ndj-reduce
```
#### examples
Suppose you have a `file.ndjson` such as:
```
{"nom":"Lausanne","population":138905}
{"nom":"Yverdon-les-Bains","population":30143}
{"nom":"Montreux","population":26574}
{"nom":"Renens","population":21036}
{"nom":"Nyon","population":20533}
{"nom":"Vevey","population":19827}
```
```bash
ndj-cat file.ndjson \
| ndj-reduce
```
without arguments, it will return
```json
[{"nom":"Lausanne","population":138905},{"nom":"Yverdon-les-Bains","population":30143},{"nom":"Montreux","population":26574},{"nom":"Renens","population":21036},{"nom":"Nyon","population":20533}]
```
```bash
ndj-cat file.ndjson \
| ndj-reduce 'a + d.population' 0
```
with arguments, it will return
```
237191
```