csv-and-array

This package currently allows for four operations with CSV files:

• return a promise that will supply a CSV-formatted UTF-8 string, reformatted as an array, from a specified file
• return a promise that will supply a CSV-formatted UTF-8 string, reformatted as an array of objects--the first "row's" cells determine the property names for each object, if the user does not provide an appropriately sized array of property names
• update the data of a specified file to reflect the values in an specified array
• write an array of arrays to a UTF-8 CSV file

Usage

Suppose there are two files named sample1.csv and sample2.csv within the ./data-store directory. sample1.csv:

00,01,02
10,11,12
20,21,22

sample2.csv:

Left,MiddleLeft,MiddleRight,Right
AA,AB,AC,AD
BA,BB,BC,BD

Now, we can access and manipulate these files as follows:

const csvAndArray = require('csv-and-array')
const sample1 = csvAndArray.csvFileAsArray('./data-store/sample1.csv')
const sample2 = csvAndArray.csvFileAsArray('./data-store/sample2.csv')

// Return a promise to supply `sample1.csv`'s values as an array of arrays.
var samp1AsArrPromise = sample1.getValues()
samp1AsArrPromise.then(console.log)
/* expected output:
    --> [['00','01','02'],['10','11','12'],['20','21','22']]
*/

// Change the values within `sample2.csv` by
// applying a transforming function to the analogous array of arrays,
// and return a promise to supply the file's new content as a UTF-8 string.
sample2.changeValues(
  arr=>arr.concat([['CA','CB','CC','CD']])
)
// Check to see impact of the changes. 
sample2.getValues().then(console.log)
/* expected output:
    --> [
         ['Left','MiddleLeft','MiddleRight','Right'],
         ['AA','AB','AC','AD'],
         ['BA','BB','BC','BD'],
         ['CA','CB','CC','CD']
        ]
*/

// Return a promise to supply `sample2.csv`'s values as an array of objects
// with the file's first row dictating the property names for each subsequent
// row's analogous object property:(cell value) pairs.
var samp2AsObjPromise = sample2.getValuesAsObj()
samp2AsObjPromise.then(console.log)
/* expected output:
    --> [
         { Left: 'AA', MiddleLeft: 'AB', MiddleRight: 'AC', Right: 'AD' },
         { Left: 'BA', MiddleLeft: 'BB', MiddleRight: 'BC', Right: 'BD' },
         { Left: 'CA', MiddleLeft: 'CB', MiddleRight: 'CC', Right: 'CD' }
        ]
*/

// Return a promise to supply `sample1.csv`'s values as an array of objects
// with the property names provided in the array ['l','m','r'] for each
// row's analogous object property:(cell value) pairs.
var samp1AsObjPromise = sample1.getValuesAsObj(['l','m','r'])
samp1AsObjPromise.then(console.log)
/* expected output:
    --> [
         { l: '00', m: '01', r: '02' },
         { l: '10', m: '11', r: '12' },
         { l: '20', m: '21', r: '22' }
        ]
*/

Finally, we can write a UTF-8 CSV file named sample3.csv from an array of arrays to the directory ./data-store:

const csvAndArray = require('csv-and-array')
var sample3Arr = [[1,2,3,4],[2,4,6,8],[3,6,9,12]]

csvAndArray.arrayToCSVFile('./data-store/sample3.csv',sample3Arr)
// expected output --> 'success'

We should now see the following content in sample3.csv:

1,2,3,4
2,4,6,8
3,6,9,12