map-tabular-keys

1.0.0 • Public • Published

map-tabular-keys

Transform the keys of a tabular object stream with a map function. Because the data is assumed to be tabular, only the keys of the first row are mapped. The resulting keys are then used for all rows.

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example

var map    = require('map-tabular-keys')
  , snake  = require('snake-case')
  , from   = require('from2-array')
  , concat = require('concat-stream')
 
from.obj([
  { 'column a': 3, columnB: 0.2 },
  { 'column a': 4, columnB: 0.3, ignored: true }
])
 
.pipe( map(snake) )
.pipe( concat(console.log.bind(console)) )

The output would be:

[
  { column_a: 3, column_b: 0.2 },
  { column_a: 4, column_b: 0.3 }
]

api

map([options], mapFunction)

mapFunction receives a single argument, for every key of the first row. If it returns an empty string or anything other than a string, the key is ignored (i.e., not included in the emitted objects).

map(function(key) {
  if (key === 'useless') return false
  return key.toUpperCase()
})

Options:

  • defaultValue: mixed (default is 0): fallback to use for null and undefined values
  • bare: boolean (default is false): whether to emit bare objects (created with Object.create(null)) or plain objects

install

With npm do:

npm install map-tabular-keys

license

MIT © Vincent Weevers

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Install

npm i map-tabular-keys

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2

Version

1.0.0

License

MIT

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Collaborators

  • vweevers