deno-ndjson

CLI tools for dealing with ndjson in Deno. Heavily inspired by ndjson-cli for node.

ndj-cat

reads a ndjson file into the console line by line

install

deno install --allow-read https://raw.githubusercontent.com/idris-maps/deno-ndjson/master/ndj-cat.ts

usage

ndj-cat <PATH_TO_NDJSON_FILE>

example

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

deno install https://raw.githubusercontent.com/idris-maps/deno-ndjson/master/ndj-map.ts

usage

ndj-map <EXPRESSION>

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}

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

deno install https://raw.githubusercontent.com/idris-maps/deno-ndjson/master/ndj-filter.ts

usage

ndj-filter <EXPRESSION>

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}

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

deno install https://raw.githubusercontent.com/idris-maps/deno-ndjson/master/ndj-reduce.ts

usage

ndj-reduce

## or

ndj-reduce <EXPRESSION> <INITIAL_VALUE>

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}

ndj-cat file.ndjson \
| ndj-reduce

without arguments, it will return

[{"nom":"Lausanne","population":138905},{"nom":"Yverdon-les-Bains","population":30143},{"nom":"Montreux","population":26574},{"nom":"Renens","population":21036},{"nom":"Nyon","population":20533}]

ndj-cat file.ndjson \
| ndj-reduce 'a + d.population' 0

with arguments, it will return

237191