@MomsFriendlyDevCo/express-middleware-formatter

Express middleware to provide alternate formatting of data when requested.

Simple example

var emf = require('@momsfriendlydevco/express-middleware-formatter');

app.get('/api/data', emf(), function(req, res) {
	res.send(someData);
});

# If /api/data is requested - normal JSON will be sent
# If /api/data?format=csv - JSON data will be transformed into CSV
# If /api/data?format=xlsx - JSON data will be transformed into XLSX
# etc.

API

emf([options])

Function which returns formatting middleware.

Supported options:

Option	Type	Default	Description
filename	string	Unset	If set this will be the filename used for any output format that requires a filename, overriding their own format specific filenames
forceArray	boolean	false	Wrap the data in an array if the data provided is an object
format	string or function	See source	Forced format to return as a string or if a function how to determine the format. By default this uses the req.query.format property if present
key	string	null	Extract tabular data from this key path (dotted or array notation is supported) instead of assuming the whole JSON response is the tabular data
unpack	function or array <function>	Undefined	A function or array of functions to run to mangle the data into something that can be processed, promise returns are supported. Called as (data, req, res, settings)
csv	object		CSV specific options
csv.filename	string	"Exported Data.csv"	Default filename when exporting as CSV
html	object		HTML specific options
html.download	boolean	false	If false, the HTML will be shown in the browser, if true the file will be forced as a download
html.filename	string	"Exported Data.html"	Default filename when exporting as HTML
html.footer	string	(Simple HTML footer)	Set the HTML suffix after outputting the body content for HTML
html.header	string	(Simple HTML header)	Set the HTML prefix before outputting the body content for HTML
html.passthru	boolean	false	Force the HTML output plugin to compute the data but not resolve the response - used internally by upstream formatters like pdf
ods	object		ODS specific options
ods.filename	string	"Exported Data.ods"	Default filename when exporting as ODS
pdf	object		PDF specific options
pdf.download	boolean	true	If false, the PDF will be shown in the browser (if the browser supports it), if true the file will be forced as a download
pdf.filename	string	"Exported Data.pdf"	Default filename when exporting as PDF
xlsx	object		XLSX specific options
xlsx.checkArray	boolean	true	Verify that the input is an array, disable this if picking your own fields when using xlsx.template
xlsx.filename	string	"Exported Data.xlsx"	Default filename when exporting as XLSX
xlsx.sheetName	string	"Exported Data"	Default sheet name in the exported file
xlsx.template	string or function		If specified use @mfdc/spreadsheet-templater to format the XLSX output (see notes)
xlsx.templateData	function	(req, res, settings, content) => content	How to mangle the content data before its passed to @mfdc/spreadsheet-templater

NOTES:

• Since EMF has to extend the res.send() / res.json() Express functions, EMF must be installed as a middleware before calls to those functions occur. Thus: app.get('/somwhere', emf(), (res, res) => ...) is valid, app.get('/somwhere', (res, res) => ..., emf()) is not.
• Extracting data from a specified key occurs before unpack is processed
• An array of items in unpack are evaluated in series, any combination of simple function return and promise return are supported
• If xlsx.template is specified or if it returns a path to a valid file it the input data (post unpack) will be passed to @mfdc/spreadsheet-templater for formatting. This allows a template XLSX file which gets passed the input data
• If xlsx.template is a function it is called as (req, res, emfSettings, content)
• If xlsx.template is an async function or returns a promise it will be resolved asynchronously before continuing
• As with the above point @mfdc/spreadsheet-templater is an optional dependency and must be installed at the project level if xlsx.template is specified

emf.formats

An object of all the supported output formats. The key is the short format name (csv, pdf etc.) with the key as the export of the format module.

emf.flatten(object)

Function used internally to take a nested object and return an flattened object in dotted notation.

emf.unflatten(object)

Function used internally to expand dotted notation object keys into a nested object.