[tests]: http://img.shields.io/travis/mafintosh/csv-parser.svg [tests-url]: http://travis-ci.org/mafintosh/csv-parser [cover]: https://codecov.io/gh/mafintosh/csv-parser/branch/master/graph/badge.svg [cover-url]: https://codecov.io/gh/mafintosh/csv-parser [size]: https://packagephobia.now.sh/badge?p=csv-parser [size-url]: https://packagephobia.now.sh/result?p=csv-parser # csv-parser [![tests][tests]][tests-url] [![cover][cover]][cover-url] [![size][size]][size-url] Streaming CSV parser that aims for maximum speed as well as compatibility with the [csv-spectrum](https://npmjs.org/csv-spectrum) CSV acid test suite. `csv-parser` can convert CSV into JSON at at rate of around 90,000 rows per second. Performance varies with the data used; try `bin/bench.js ` to benchmark your data. `csv-parser` can be used in the browser with [browserify](http://browserify.org/). [neat-csv](https://github.com/sindresorhus/neat-csv) can be used if a `Promise` based interface to `csv-parser` is needed. _Note: This module requires Node v8.16.0 or higher._ ## Benchmarks ⚡️ `csv-parser` is greased-lightning fast ```console → npm run bench Filename Rows Parsed Duration backtick.csv 2 3.5ms bad-data.csv 3 0.55ms basic.csv 1 0.26ms comma-in-quote.csv 1 0.29ms comment.csv 2 0.40ms empty-columns.csv 1 0.40ms escape-quotes.csv 3 0.38ms geojson.csv 3 0.46ms large-dataset.csv 7268 73ms newlines.csv 3 0.35ms no-headers.csv 3 0.26ms option-comment.csv 2 0.24ms option-escape.csv 3 0.25ms option-maxRowBytes.csv 4577 39ms option-newline.csv 0 0.47ms option-quote-escape.csv 3 0.33ms option-quote-many.csv 3 0.38ms option-quote.csv 2 0.22ms quotes+newlines.csv 3 0.20ms strict.csv 3 0.22ms latin.csv 2 0.38ms mac-newlines.csv 2 0.28ms utf16-big.csv 2 0.33ms utf16.csv 2 0.26ms utf8.csv 2 0.24ms ``` ## Install Using npm: ```console $ npm install csv-parser ``` Using yarn: ```console $ yarn add csv-parser ``` ## Usage To use the module, create a readable stream to a desired CSV file, instantiate `csv`, and pipe the stream to `csv`. Suppose you have a CSV file `data.csv` which contains the data: ``` NAME,AGE Daffy Duck,24 Bugs Bunny,22 ``` It could then be parsed, and results shown like so: ``` js const csv = require('csv-parser') const fs = require('fs') const results = []; fs.createReadStream('data.csv') .pipe(csv()) .on('data', (data) => results.push(data)) .on('end', () => { console.log(results); // [ // { NAME: 'Daffy Duck', AGE: '24' }, // { NAME: 'Bugs Bunny', AGE: '22' } // ] }); ``` To specify options for `csv`, pass an object argument to the function. For example: ```js csv({ separator: '\t' }); ``` ## API ### csv([options | headers]) Returns: `Array[Object]` #### options Type: `Object` As an alternative to passing an `options` object, you may pass an `Array[String]` which specifies the headers to use. For example: ```js csv(['Name', 'Age']); ``` If you need to specify options _and_ headers, please use the the object notation with the `headers` property as shown below. #### escape Type: `String`
Default: `"` A single-character string used to specify the character used to escape strings in a CSV row. #### headers Type: `Array[String] | Boolean` Specifies the headers to use. Headers define the property key for each value in a CSV row. If no `headers` option is provided, `csv-parser` will use the first line in a CSV file as the header specification. If `false`, specifies that the first row in a data file does _not_ contain headers, and instructs the parser to use the column index as the key for each column. Using `headers: false` with the same `data.csv` example from above would yield: ``` js [ { '0': 'Daffy Duck', '1': 24 }, { '0': 'Bugs Bunny', '1': 22 } ] ``` _Note: If using the `headers` for an operation on a file which contains headers on the first line, specify `skipLines: 1` to skip over the row, or the headers row will appear as normal row data. Alternatively, use the `mapHeaders` option to manipulate existing headers in that scenario._ #### mapHeaders Type: `Function` A function that can be used to modify the values of each header. Return a `String` to modify the header. Return `null` to remove the header, and it's column, from the results. ```js csv({ mapHeaders: ({ header, index }) => header.toLowerCase() }) ``` ##### Parameters **header** _String_ The current column header.
**index** _Number_ The current column index. #### mapValues Type: `Function` A function that can be used to modify the content of each column. The return value will replace the current column content. ```js csv({ mapValues: ({ header, index, value }) => value.toLowerCase() }) ``` ##### Parameters **header** _String_ The current column header.
**index** _Number_ The current column index.
**value** _String_ The current column value (or content). ##### newline Type: `String`
Default: `\n` Specifies a single-character string to denote the end of a line in a CSV file. #### quote Type: `String`
Default: `"` Specifies a single-character string to denote a quoted string. #### raw Type: `Boolean`
If `true`, instructs the parser not to decode UTF-8 strings. #### separator Type: `String`
Default: `,` Specifies a single-character string to use as the column separator for each row. #### skipComments Type: `Boolean | String`
Default: `false` Instructs the parser to ignore lines which represent comments in a CSV file. Since there is no specification that dictates what a CSV comment looks like, comments should be considered non-standard. The "most common" character used to signify a comment in a CSV file is `"#"`. If this option is set to `true`, lines which begin with `#` will be skipped. If a custom character is needed to denote a commented line, this option may be set to a string which represents the leading character(s) signifying a comment line. #### skipLines Type: `Number`
Default: `0` Specifies the number of lines at the beginning of a data file that the parser should skip over, prior to parsing headers. #### maxRowBytes Type: `Number`
Default: `Number.MAX_SAFE_INTEGER` Maximum number of bytes per row. An error is thrown if a line exeeds this value. The default value is on 8 peta byte. #### strict Type: `Boolean`
Default: `false` If `true`, instructs the parser that the number of columns in each row must match the number of `headers` specified or throws an exception. if `false`: the headers are mapped to the column index less columns: any missing column in the middle will result in a wrong property mapping! more columns: the aditional columns will create a "_"+index properties - eg. "_10":"value" ## Events The following events are emitted during parsing: ### `data` Emitted for each row of data parsed with the notable exception of the header row. Please see [Usage](#Usage) for an example. ### `headers` Emitted after the header row is parsed. The first parameter of the event callback is an `Array[String]` containing the header names. ```js fs.createReadStream('data.csv') .pipe(csv()) .on('headers', (headers) => { console.log(`First header: ${headers[0]}`) }) ``` ### Readable Stream Events Events available on Node built-in [Readable Streams](https://nodejs.org/api/stream.html#stream_class_stream_readable) are also emitted. The `end` event should be used to detect the end of parsing. ## CLI This module also provides a CLI which will convert CSV to [newline-delimited](http://ndjson.org/) JSON. The following CLI flags can be used to control how input is parsed: ``` Usage: csv-parser [filename?] [options] --escape,-e Set the escape character (defaults to quote value) --headers,-h Explicitly specify csv headers as a comma separated list --help Show this help --output,-o Set output file. Defaults to stdout --quote,-q Set the quote character ('"' by default) --remove Remove columns from output by header name --separator,-s Set the separator character ("," by default) --skipComments,-c Skip CSV comments that begin with '#'. Set a value to change the comment character. --skipLines,-l Set the number of lines to skip to before parsing headers --strict Require column length match headers length --version,-v Print out the installed version ``` For example; to parse a TSV file: ``` cat data.tsv | csv-parser -s $'\t' ``` ## Encoding Users may encounter issues with the encoding of a CSV file. Transcoding the source stream can be done neatly with a modules such as: - [`iconv-lite`](https://www.npmjs.com/package/iconv-lite) - [`iconv`](https://www.npmjs.com/package/iconv) Or native [`iconv`](http://man7.org/linux/man-pages/man1/iconv.1.html) if part of a pipeline. ## Byte Order Marks Some CSV files may be generated with, or contain a leading [Byte Order Mark](https://en.wikipedia.org/wiki/Byte_order_mark#UTF-8). This may cause issues parsing headers and/or data from your file. From Wikipedia: >The Unicode Standard permits the BOM in UTF-8, but does not require nor recommend its use. Byte order has no meaning in UTF-8. To use this module with a file containing a BOM, please use a module like [strip-bom-stream](https://github.com/sindresorhus/strip-bom-stream) in your pipeline: ```js const fs = require('fs'); const csv = require('csv-parser'); const stripBom = require('strip-bom-stream'); fs.createReadStream('data.csv') .pipe(stripBom()) .pipe(csv()) ... ``` When using the CLI, the BOM can be removed by first running: ```console $ sed $'s/\xEF\xBB\xBF//g' data.csv ``` ## Meta [CONTRIBUTING](./.github/CONTRIBUTING) [LICENSE (MIT)](./LICENSE)

	Stars	Issues	Version	Updated	Created
csv	3,866	42	6.3.9	6 days ago	13 years ago
csv-parser	1,403	52	3.0.0	3 years ago	10 years ago
json2csv			6.0.0-alpha.2	a year ago	12 years ago
jsonexport	247	17	3.2.0	3 years ago	9 years ago
papaparse			5.4.1	a year ago	10 years ago

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