mustache4dart 2.1.2

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Mustache for Dart #

Build Status Coverage Status

A simple implementation of Mustache for the Dart language, which passes happily all the mustache v1.1.2+λ specs. If you want to have a look at how it works, just check the tests. For more info, just read further.

Using it #

In order to use the library, just add it to your pubspec.yaml as a dependency

  mustache4dart: '>= 2.0.0 < 3.0.0'

and then import the package

import 'package:mustache4dart/mustache4dart.dart';

and you are good to go. You can use the render toplevel function to render your template.

For example:

var salutation = render('Hello {{name}}!', {'name': 'Bob'});
print(salutation); //shoud print Hello Bob!

Context objects #

mustache4dart will look at your given object for operators, fields or methods. For example, if you give the template {{firstname}} for rendering, mustache4dart will try the followings

  1. use the [] operator with firstname as the parameter
  2. search for a field named firstname
  3. search for a getter named firstname
  4. search for a method named firstname (see Lambdas support)

in each case the first valid value will be used.


In order to do the stuff described above the mirror library is being used which could lead to big js files when compiling the library with dartjs. In order to preserve the type information you have to annotate the objects used as contextes with @MirrorsUsed. Have in mind though that as documented this is experimental.

In order to avoid the use of the mirrors package, make sure that you compile your library with dart2js -DMIRRORS=false. In that case though you must always make sure that your context object have a right implementation of the [] operator as no other checks on the object will be available.

Partials #

mustache4dart support partials but it needs somehow to know how to find a partial. You can do that by providing a function that returns a template given a name:

String partialProvider(String partialName) => "this is the partial with name: ${partialName}";
expect(render('[{{>p}}]', null, partial: partialProvider), '[this is the partial with name: p]'));

Compiling to functions #

If you have a template that you are going to reuse with different contexts, you can compile it to a function using the toplevel function compile:

var salut = compile('Hello {{name}}!');
print(salut({'name': 'Alice'})); //should print Hello Alice!

Lambdas support #

The library passes all the optional lambda specs based on which lambdas must be treatable as arity 0 or 1 functions. As dart provides optional named parameters, you can pass to a given lambda function the nestedContext. In that case the current nested context will be given as parameter to the lambda function.

Developing #

The project passes all the Mustache specs. You have to make sure though that you've downloaded them. Just make sure that you have done the steps described below.

git clone git://
git submodule init
git submodule update
pub get

If you are with Linux, you can use what travis does:


Alternatively, if you have Dart Test Runner installed you can just do:

pub global run test_runner

Observatory #

To start the observatory after running test:

dart --pause-isolates-on-exit --enable-vm-service=NNNN ./test/mustache_all.dart

Then coverage can be used in order to collect and format data:

pub global run coverage:collect_coverage --uri=http://... -o /tmp/mustache4dart.coverage.json --resume-isolates
pub global run coverage:format_coverage --packages=app_package/.packages -i /tmp/mustache4dart.coverage.json

Contributing #

If you found a bug, just create a new issue or even better fork and issue a pull request with you fix.

Versioning #

The library will follow a semantic versioning


2.1.1 (2018-04-14) #

  • Addressed Dart 2 analysis issues #70
  • Run tests against v2 vm of Dart

2.1.0 (2017-06-21) #

  • Mirrors improvements #65

2.0.0 (2017-06-13) #

  • Rework MustacheContext (#64)
  • Use dartanalyzer --strong mode (#61)

As part of the MustacheContext rework, a couple of simplifications have been made. Most notable one is the drop support of mirroring methods starting with get as it does not make any sense with dart. Use a getter instead.

1.1.0 (2017-05-10) #

  • Avoid trapping exceptions by using reflection (#59)

1.0.12 (2017-03-17) #

  • Maintenance release

1.0.11 (2017-03-02) #

  • Fixed issue with default value of boolean arguments
  • Compile method now returns type annotation issue

1.0.10 (2015-03-15) #

  • Allow iterables to get queried for empty or isEmpty attribute issue

1.0.9 (2015-02-13) #

  • throw exception on missing property (helps debugging and tracking down errors) issue
  • introduced assumeNullNonExistingProperty (the difference between a null field and a non-existent field) issue
  • Provide lambdas with the current nested context when they have two parameters (lambdas can now render their contents when inside of a loop) issue

1.0.8 (2015-02-01) #

  • Find property names in superclasses issue

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:

  mustache4dart: ^2.1.2

2. Install it

You can install packages from the command line:

with pub:

$ pub get

Alternatively, your editor might support pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:

import 'package:mustache4dart/mustache4dart.dart';
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The package version is not analyzed, because it does not support Dart 2. Until this is resolved, the package will receive a health and maintenance score of 0.

Analysis issues and suggestions

Support Dart 2 in pubspec.yaml.

The SDK constraint in pubspec.yaml doesn't allow the Dart 2.0.0 release. For information about upgrading it to be Dart 2 compatible, please see


Package Constraint Resolved Available
Direct dependencies
Dart SDK >=0.8.10+6 <2.0.0