csv
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CSV parser with simple api, full of options and tested against large datasets.
243 lines (198 loc) • 7.25 kB
JavaScript
// Generated by CoffeeScript 1.6.2
var Stream, fs, utils;
fs = require('fs');
Stream = require('stream');
utils = require('./utils');
/*
Writing data to a destination
=============================
The `csv().to` property provides functions to read from a CSV instance and
to write to an external destination. The destination may be a stream, a file
or a callback.
You may call the `to` function or one of its sub function. For example,
here are two identical ways to write to a file:
csv.from(data).to('/tmp/data.csv');
csv.from(data).to.path('/tmp/data.csv');
*/
module.exports = function(csv) {
/*
`to(mixed)`
-----------
Write from any sort of destination. It should be considered as a convenient function
which will discover the nature of the destination where to write the CSV data.
If is an function, then the csv will be provided as the first argument
of the callback. If it is a string, then it is expected to be a
file path. If it is an instance of stream, it consider the object to be an
output stream.
Here's some examples on how to use this function:
csv()
.from('"1","2","3","4","5"')
.to(function(data){ console.log(data) })
csv()
.from('"1","2","3","4","5"')
.to('./path/to/file.csv')
csv()
.from('"1","2","3","4","5"')
.to(fs.createWriteStream('./path/to/file.csv'))
*/
var to;
to = function(mixed, options) {
var error;
error = false;
switch (typeof mixed) {
case 'string':
to.path(mixed, options);
break;
case 'object':
if (mixed instanceof Stream) {
to.stream(mixed, options);
} else {
error = true;
}
break;
case 'function':
to.string(mixed, options);
break;
default:
error = true;
}
if (error) {
csv.error(new Error("Invalid mixed argument in from"));
}
return csv;
};
/*
`to.options([options])`
-----------------------
Update and retrieve options relative to the output. Return the options
as an object if no argument is provided.
* `delimiter` Set the field delimiter, one character only, defaults to `options.from.delimiter` which is a comma.
* `quote` Defaults to the quote read option.
* `quoted` Boolean, default to false, quote all the fields even if not required.
* `escape` Defaults to the escape read option.
* `columns` List of fields, applied when `transform` returns an object, order matters, see the transform and the columns sections below.
* `header` Display the column names on the first line if the columns option is provided.
* `lineBreaks` String used to delimit record rows or a special value; special values are 'auto', 'unix', 'mac', 'windows', 'unicode'; defaults to 'auto' (discovered in source or 'unix' if no source is specified).
* `flags` Defaults to 'w', 'w' to create or overwrite an file, 'a' to append to a file. Applied when using the `toPath` method.
* `newColumns` If the `columns` option is not specified (which means columns will be taken from the reader options, will automatically append new columns if they are added during `transform()`.
* `end` Prevent calling `end` on the destination, so that destination is no longer writable.
* `eof` Add a linebreak on the last line, default to false, expect a charactere or use '\n' if value is set to "true"
The end options is similar to passing `{end: false}` option in `stream.pipe()`. According to the Node.js documentation:
> By default end() is called on the destination when the source stream emits end, so that destination is no longer writable. Pass { end: false } as options to keep the destination stream open.
*/
to.options = function(options) {
if (options != null) {
utils.merge(csv.options.to, options);
if (csv.options.to.lineBreaks) {
console.log('To options linebreaks is replaced by rowDelimiter');
if (!csv.options.to.rowDelimiter) {
csv.options.to.rowDelimiter = csv.options.to.lineBreaks;
}
}
switch (csv.options.to.rowDelimiter) {
case 'auto':
csv.options.to.rowDelimiter = null;
break;
case 'unix':
csv.options.to.rowDelimiter = "\n";
break;
case 'mac':
csv.options.to.rowDelimiter = "\r";
break;
case 'windows':
csv.options.to.rowDelimiter = "\r\n";
break;
case 'unicode':
csv.options.to.rowDelimiter = "\u2028";
}
return csv;
} else {
return csv.options.to;
}
};
/*
`to.string(callback, [options])`
------------------------------
Provide the output string to a callback.
csv()
.from( '"1","2","3"\n"a","b","c"' )
.to.string( function(data, count){} )
Callback is called with 2 arguments:
* data Entire CSV as a string
* count Number of stringified records
*/
to.string = function(callback, options) {
var data, stream;
this.options(options);
data = '';
stream = new Stream;
stream.writable = true;
stream.write = function(d) {
data += d;
return true;
};
stream.end = function() {
return callback(data, csv.state.countWriten);
};
csv.pipe(stream);
return csv;
};
/*
`to.stream(stream, [options])`
------------------------------
Write to a stream. Take a writable stream as first argument and
optionally an object of options as a second argument.
*/
to.stream = function(stream, options) {
this.options(options);
csv.pipe(stream, csv.options.to);
stream.on('error', function(e) {
return csv.error(e);
});
stream.on('close', function() {
return csv.emit('close', csv.state.count);
});
return csv;
};
/*
`to.path(path, [options])`
--------------------------
Write to a path. Take a file path as first argument and optionally an object of
options as a second argument. The `close` event is sent after the file is written.
Relying on the `end` event is incorrect because it is sent when parsing is done
but before the file is written.
*/
to.path = function(path, options) {
var stream;
this.options(options);
options = utils.merge({}, csv.options.to);
delete options.end;
stream = fs.createWriteStream(path, options);
csv.to.stream(stream, null);
return csv;
};
/*
`to.array(path, [options])`
--------------------------
Provide the output string to a callback.
csv()
.from( '"1","2","3"\n"a","b","c"' )
.to.array( function(data, count){} )
Callback is called with 2 arguments:
* data Entire CSV as an array of records
* count Number of stringified records
*/
to.array = function(callback, options) {
var records;
this.options(options);
records = [];
csv.on('record', function(record) {
return records.push(record);
});
csv.on('end', function() {
return callback(records, csv.state.countWriten);
});
return csv;
};
return to;
};