Files
30-seconds-of-code/snippets/CSVToJSON.md
Mathias Bynens 8ee50178f3 Avoid confusing prototype methods for static methods
Correct: `Array.from()` (it’s a static method)
Incorrect: `Array.join()` (doesn’t exist; it’s a prototype method)

This patch uses the common `#` syntax to denote `.prototype.`.
2018-09-28 15:44:12 -04:00

28 lines
1.2 KiB
Markdown

### CSVToJSON
Converts a comma-separated values (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 `,`.
```js
const CSVToJSON = (data, delimiter = ',') => {
const titles = data.slice(0, data.indexOf('\n')).split(delimiter);
return data
.slice(data.indexOf('\n') + 1)
.split('\n')
.map(v => {
const values = v.split(delimiter);
return titles.reduce((obj, title, index) => ((obj[title] = values[index]), obj), {});
});
};
```
```js
CSVToJSON('col1,col2\na,b\nc,d'); // [{'col1': 'a', 'col2': 'b'}, {'col1': 'c', 'col2': 'd'}];
CSVToJSON('col1;col2\na;b\nc;d', ';'); // [{'col1': 'a', 'col2': 'b'}, {'col1': 'c', 'col2': 'd'}];
```