JavaScript: Convert a 2D array to a comma-separated values (CSV) string

JavaScript fundamental (ES6 Syntax): Exercise-257 with Solution

2D Array to CSV

Write a JavaScript program to convert a 2D array to a comma-separated value (CSV) string.

• Use Array.prototype.map() and Array.prototype.join(delimiter) to combine individual 1D arrays (rows) into strings.
• Use Array.prototype.join('\n') to combine all rows into a CSV string, separating each row with a newline.
• Omit the second argument, delimiter, to use a default delimiter of ,.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
// Define a function 'arrayToCSV' to convert a 2D array into a CSV string with a specified delimiter
const arrayToCSV = (arr, delimiter = ',') =>
  // Map each row of the array, converting each value into a string enclosed in double quotes and joined by the specified delimiter
  arr.map(v => v.map(x => `"${x}"`).join(delimiter)).join('\n');

// Test the 'arrayToCSV' function with a 2D array and default and custom delimiters
console.log(arrayToCSV([['a', 'b'], ['c', 'd']])); // "a","b"\n"c","d" (CSV string with default delimiter ',')
console.log(arrayToCSV([['a', 'b'], ['c', 'd']], ';')); // "a";"b"\n"c";"d" (CSV string with custom delimiter ';')

Output:

"a","b"
"c","d"
"a";"b"
"c";"d"

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-257-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that converts a two-dimensional array into a CSV-formatted string.
• Write a JavaScript function that maps each sub-array to a comma-separated string and joins them with newlines.
• Write a JavaScript program that handles arrays with varying lengths and outputs a properly formatted CSV.
• Write a JavaScript function that escapes commas in values and converts a 2D array into a valid CSV string.

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