JavaScript : Convert a comma-separated values string to a 2D array of objects

JavaScript fundamental (ES6 Syntax): Exercise-4 with Solution

CSV to 2D Array of Objects

Write a JavaScript program to convert a comma-separated value (CSV) string to a 2D array of objects. The first row of the string is used as the title row.

• Use Array.prototype.slice() and Array.prototype.indexOf('\n') and String.prototype.split(delimiter) to separate the first row (title row) into values.
• Use String.prototype.split('\n') to create a string for each row, then Array.prototype.map() and String.prototype.split(delimiter) to separate the values in each row.
• Use Array.prototype.reduce() to create an object for each row's values, with the keys parsed from the title row.
• Omit the second argument, delimiter, to use a default delimiter of ,.

Sample Solution:

JavaScript Code:

// Source: https://bit.ly/2neWfJ2

// Define a function called `CSV_to_JSON` that converts CSV data to a JSON array.
const CSV_to_JSON = (data, delimiter = ',') => {
  // Extract titles from the first row of the CSV data.
  const titles = data.slice(0, data.indexOf('\n')).split(delimiter);
  // Split the CSV data by newline characters, map each row to a JSON object with titles as keys.
  return data
    .slice(data.indexOf('\n') + 1)
    .split('\n')
    .map(v => {
      const values = v.split(delimiter);
      // Create a JSON object using titles and corresponding values.
      return titles.reduce((obj, title, index) => ((obj[title] = values[index]), obj), {});
    });
};

// Test cases
console.log(CSV_to_JSON('col1,col2\na,b\nc,d')); // [{'col1': 'a', 'col2': 'b'}, {'col1': 'c', 'col2': 'd'}];
console.log(CSV_to_JSON('col1;col2\na;b\nc;d', ';')); // [{'col1': 'a', 'col2': 'b'}, {'col1': 'c', 'col2': 'd'}];

Output:

[{"col1":"a","col2":"b"},{"col1":"c","col2":"d"}]
[{"col1":"a","col2":"b"},{"col1":"c","col2":"d"}]

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-1-4 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that converts a CSV string into an array of objects using the first row as keys.
• Write a JavaScript function that transforms CSV data into an array of objects, handling missing fields gracefully.
• Write a JavaScript program that parses a CSV string and returns an array of objects with trimmed and normalized property names.

Improve this sample solution and post your code through Disqus

Previous: Write a JavaScript program to converts a comma-separated values (CSV) string to a 2D array.
Next: Write a JavaScript program to convert an array of objects to a comma-separated values (CSV) string that contains only the columns specified.