formatted-stream

A universal wrapper around file format parsers.
Currently supports in- and output in CSV, JSON, and XLSX format.

## Usage

Install formatted-stream:

npm install formatted-stream --save

Include and use in your code:

ES5

const fs = require('fs'),
  formattedStream = require('formatted-stream').default,
  parser = formattedStream.from('json'),
  writer = formattedStream.to('csv');

parser.pipe(writer);
writer.pipe(fs.createWriteStream('out.csv'));
fs.createReadStream('in.json').pipe(parser);

ES6

import fs from 'fs';
import formattedStream from 'formatted-stream';

const parser = formattedStream.from('json'),
  writer = formattedStream.to('csv');

parser.pipe(writer);
writer.pipe(fs.createWriteStream('out.csv'));
fs.createReadStream('in.json').pipe(parser);

## API Documentation

### .from(format, options)

const parser = formattedStream.from('csv', {
  transform: function(data) { return data; },
  csv: {headers: false}
});

format

Type String. Must be either xlsx, json, or csv.

options.transform

Type Function. A transformation function which is applied to each object before .on('data') is triggered.
Default is function(data) { return data; }.

options.csv

Type Object. An options object which will be passed to the CSV parser.
See fast-csv for more information.
Default is {headers: true}.

#### options.json

Type Object. The value of options.json.path will be passed to JSONStream.parse.
See JSONStream for more information.
Default is {path: [true]}.

options.xlsx

Type Object. An options object which will be passed to the XLSX parser. Set the XLSX worksheet by defining options.xlsx.sheet. Default: Sheet 1
See ExcelJS for more options.
Default is {sheet: 'Sheet 1'}.

### .to(format, options)

const writer = formattedStream.to('json', {
  transform: function(data) { return data; },
  csv: {headers: false},
  json: {
    open: '[\n',
    sep: '\n,\n',
    close: '\n]\n'
  }
});

format

Type String. Must be either xlsx, json, or csv.

options.transform

Type Function. A transformation function which is applied to each object before .on('data') is triggered.
Default is function(data) { return data; }.

options.csv

Type Object. An options object which will be passed to the CSV writer.
See fast-csv for more information.
Default is {}.

options.json

Type Object. An options object which will be passed to the JSON writer.
See JSONStream for more information.
Default is {}.

options.xlsx

Type Object. An options object which will be passed to the XLSX writer. Assign a function to options.xlsx.headerAccessor in order to transform all header fields according to the output of the function. Set the XLSX worksheet by defining options.xlsx.sheet. If no sheet is defined, the XLSX parser will write all sheets in the document to the CSV file. Default: undefined.
See ExcelJS for more options.
Default is {}.