tabular-stream
v4.0.0
Published
Detects tabular data (spreadsheets, dsv or json) and emits normalized objects
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Readme
tabular-stream
Note: the core of
tabular-stream
1.0 has moved todetect-tabular
. This is now a data normalizer on top of that.
Detects tabular data (spreadsheets, dsv or json, 20+ different formats) and emits objects. Ensures all rows have the same keys, optionally transforms keys and tries to coerce values to numbers. Spreadsheets and DSV must have a header.
Example
npm i tabular-stream snake-case format-data
const tabular = require('tabular-stream')
const fs = require('fs')
const snake = require('snake-case').snakeCase
const format = require('format-data')
fs.createReadStream('test/air_pollution_nl.xlsx')
.pipe(tabular(snake))
.pipe(format('json'))
.pipe(process.stdout)
Need a CLI doing just this? Jump to tabular-cli
, which pairs tabular-stream
with format-data
to convert tabular data to json, ndjson, dsv or sse. For example:
tabular -k snake-case -o tsv < input.xls > output.tsv
API
tabular([keys || options])
Returns a duplex stream - give it any tabular data, get back objects. (keys)
is a shorthand for ({ keys: keys })
. The available options are:
function keys
An optional function to transform and/or filter keys. Receives a single argument, for every key of the first row. Everything at change-case
works well. If it returns an empty string or anything other than a string, the key is ignored (i.e. not included in the emitted objects).
function keys(key) {
if (key === 'useless') return false
return key.toUpperCase()
}
mixed defaultValue
Fallback value to use for null
and undefined
values. Default is 0
.
boolean bare
Whether to emit null prototype objects via Object.create(null)
or plain javascript objects (the default).
Other
Other options are passed as-is to spreadsheet-stream
(if applicable). NB. Because the binary spreadsheets formats are not streamable, spreadsheet-stream
will buffer the whole thing in memory. As a safe-guard you can set the maxSize
option (in bytes): tabular({ maxSize: 1024 * 1024 })
. See spreadsheet-stream
for details.
Install
With npm do:
npm install tabular-stream
License
MIT.
Test data © Statistics Netherlands, The Hague/Heerlen.