jsreport is platform providing dynamic documents assembling and printing. It supports various document types or printing techniques.
jsreport-core contains the jsreport rendering core which is useless alone. It is up to you which extensions from the long list you additionally apply and which document printing techniques you use.
Next to the engine you need also something we call recipe. Recipe represents the technique which is used to print the document. This can be html to pdf conversion, excel rendering and others. In this example lets pick jsreport-chrome-pdf from the list of supported recipes. This recipe implements html to pdf conversion using chrome. So in this example we use handlebars to assemble html based on the input data and then print the output into final pdf.
jsreport-core by default auto discovers installed extensions and apply them. In other words it is enough to just install following packages and there is no need for other configuration.
npm install jsreport-core
npm install jsreport-handlebars
npm install puppeteer jsreport-chrome-pdf
const jsreport =jsreport
render is the main method which invokes report generation. The only parameter is an object representing rendering request. The request has following structure:
In case you have the template stored in the jsreport templates store, you can reference the template using name or path.
template:name: '/myfolder/mytemplate'data: foo: "hello world"...
The render returns promise with the single response value
//node.js buffer with the documentcontent: ...//stream with the documentstream: ...//object containing metadata about the report generation (reportName, logs, etc)..meta: ...
The convention is that jsreport repository extension starts with
jsreport-xxx, but the extension real name and also the recipes or engines it registers excludes the
jsreport- prefix. This means if you install extension
jsreport-handlebars the engine's name you specify in the render should be
By default you need to send helpers to the template in the string. This is because jsreport runs the template rendering by default in the external process to avoid freezing the application when there is an endless loop or other critical error in the helper. If you want to use your local functions for the helpers you need to switch templating engine rendering strategy to
const jsreport =templatingEngines: strategy: 'in-process'jsreport
Require in the helpers
jsreport by default runs helpers in the sandbox where is the
require function blocked. To unblock particular modules or local scripts you need to configure
const jsreport =templatingEngines: allowedModules: 'moment'// or unblock everythingconst jsreport =templatingEngines: allowedModules: '*'
Additionally jsreport provides global variables which can be used to build the local script path and read it.
const jsreport =templatingEngines: allowedModules: '*'jsreport
The following variables are available in the global scope:
__rootDirectory - two directories up from jsreport-core
__appDirectory - directory of the script which is used when starting node
__parentModuleDirectory - directory of script which was initializing jsreport-core
As you see in the first example. Even for the simplest pdf printing you need to install additional packages(extensions). This is the philosophy of jsreport and you will need to install additional extensions very often. There are not just extensions adding support for a particular templating engine or printing technique. There are many extensions adding support for persisting templates, dynamic script evaluation or even visual html designer and API. To get the idea of the whole platform you can install the full jsreport distribution and pick what you like. Then you can go back to
jsreport-core and install extensions you need.
You are also welcome to write your own extension or even publish it to the community. See the following articles how to get started.
- Implementing custom jsreport extension
- Implementing custom jsreport recipe
- Implementing custom jsreport engine
Extensions auto discovery
jsreport by default auto discovers extensions in the application's directory tree. This means jsreport by default searches for files
jsreport.config.js which describes the extensions and applies all the extensions that are found.
jsreport extensions auto discovery slows down the startup and can be explicitly overrided using
const jsreport = ...jsreportjsreportjsreport
jsreport accepts options as the first parameter. The core options are the following:
// optionally specifies where's the application root and where jsreport searches for extensionsrootDirectory: path// optionally specifies where the application stores temporary files used by the conversion pipelinetempDirectory: path// options for logginglogger:silent: false // when true, it will silence all transports defined in logger// options for templating engines and other scripts execution// see the for more informationtemplatingEngines:numberOfWorkers: 2strategy: "http-server | dedicated-process | in-process"templateCache:max: 100 //LRU cache with max 100 entries, see npm lru-cache for other optionsenabled: true //disable cacheloadConfig: false// the temporary files used to render reports are cleaned up by defaultautoTempCleanup: true// set to false when you want to always force crawling node_modules when searching for extensions and starting jsreportuseExtensionsLocationCache: true
jsreport-core is also able to load configuration from other sources including configuration file, environment variables and command line parameters. This can be opted in through option
loadConfig:true. If this option is set to true the configuration is merged from the following sources in the particular order:
- configuration file prod.config.json or dev.config.json based on the NODE_ENV
- configuration file jsreport.config.json if previous file not found
- command line arguments
- process environment variables
- options passed directly to
Each extension (recipe, store...) usually provides some options you can apply and adapt its behavior. These options can be typically set through standard configuration under the top level
extensions property, options in there with the name corresponding to the extension's name are forwarded to the particular extension. This is the common way how to globally configure all extensions at one place.
You can find configuration notes for the full jsreport distribution here.
DEBUG=jsreport node app.js
on windows do
set DEBUG=jsreport & node app.js
To declarative configure logging levels and outputs you can see this page which contains all the details for that.
jsreport also exposes
logger property which can be used to adapt the logging as you like. You can for example just add winston console transport and filter in only important log messages into console.
const winston =const jsreport =jsreportlogger
jsreport extensions are mainly using the system of event listeners to adapt the rendering process. Extension can for example listen to event which is called before the rendering process starts and adapt the input values.
//jsreport must be initialized at this timejsreportbeforeRenderListeners
To start listening you must first add the listener function to the right listener. In the example is used
beforeRenderListeners which is called before the rendering starts. jsreport then in the right time sequentially fires all the listener functions and let them do the required work. If the function returns a promise, jsreport awaits until it is fulfilled.
Note this technique can be used in extensions, but also outside in nodejs application using jsreport.
jsreport currently support these main listeners
initializeListeners()- called when all extensions are initialized
beforeRenderListeners(req, res)- very first in the rendering pipeline, used to load templates and parse input data
validateRenderListeners(req, res)- possible to reject rendering before it starts, jsut return failed promise or exception
afterTemplatingEnginesExecutedListeners(req, res)- engine like handlebars or jsrender extracted the content, the
res.contentcontains Buffer with extracted content
afterRenderListeners(req, res)- recipes are executed,
res.contentcontains final buffer which will be returned as a stream back, the last change to modify the output or send it elsewhere
renderErrorListeners(req, res, err)- fired when there is error somewhere in the rendering pipeline
closeListeners()called when jsreport is about to be closed, you will usually put here some code that clean up some resource
jsreport includes also visual html studio and rest API. This is provided through two extensions, jsreport-express extension to have a web server available and jsreport-studio for the web UI, both extensions should be installed in order to have studio ready. See the documentation of each extension for details.
jsreport-core includes API for persisting and accessing report templates. This API is then used by extensions mainly in combination with jsreport studio.
jsreport-core implements just in-memory persistence, but you can add other persistence methods through extensions. See the list.
The persistence API is almost compatible to mongodb API:
List of extensions
- jsreport-express (studio)