09s-creating-a-meteor-package.md.erb

---
title: Creating a Meteor Package
slug: creating-a-meteor-package
date: 0009/01/02
number: 9.5
sidebar: true
contents: Write a local in-app package.|Write some tests for your package.|Release your package on Atmosphere.
paragraphs: 19
---

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~~~js
Package.describe({
  name: "tmeasday:errors",
  summary: "A pattern to display application errors to the user",
  version: "1.0.0"
});

Package.onUse(function (api, where) {
  api.versionsFrom('0.9.0');
  
  api.use(['minimongo', 'mongo-livedata', 'templating'], 'client');

  api.addFiles(['errors.js', 'errors_list.html', 'errors_list.js'], 'client');
  
  if (api.export) 
    api.export('Errors');
});
~~~
<%= caption "packages/tmeasday:errors/package.js" %>

////

////

~~~js
Errors = {
  // Local (client-only) collection
  collection: new Mongo.Collection(null),
  
  throw: function(message) {
    Errors.collection.insert({message: message, seen: false})
  }
};
~~~
<%= caption "packages/tmeasday:errors/errors.js" %>

~~~html
<template name="meteorErrors">
  <div class="errors">
    {{#each errors}}
      {{> meteorError}}
    {{/each}}
  </div>
</template>

<template name="meteorError">
  <div class="alert alert-danger" role="alert">
    <button type="button" class="close" data-dismiss="alert">&times;</button>
    {{message}}
  </div>
</template>
~~~
<%= caption "packages/tmeasday:errors/errors_list.html" %>

~~~js
Template.meteorErrors.helpers({
  errors: function() {
    return Errors.collection.find();
  }
});

Template.meteorError.rendered = function() {
  var error = this.data;
  Meteor.setTimeout(function () {
    Errors.collection.remove(error._id);
  }, 3000);
};
~~~
<%= caption "packages/tmeasday:errors/errors_list.js" %>

### Testing the package out with Microscope

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~~~bash
rm client/helpers/errors.js
rm client/templates/includes/errors.html
rm client/templates/includes/errors.js
~~~
<%= caption "removing old files on the bash console" %>

////

~~~html
  {{> header}}
  {{> meteorErrors}}
~~~
<%= caption "client/templates/application/layout.html" %>

~~~js
Meteor.call('postInsert', post, function(error, result) {
  if (error) {
    // display the error to the user
    Errors.throw(error.reason);

~~~
<%= caption "client/templates/posts/post_submit.js" %>

~~~js
Posts.update(currentPostId, {$set: postProperties}, function(error) {
  if (error) {
    // display the error to the user
    Errors.throw(error.reason);
~~~
<%= caption "client/templates/posts/post_edit.js" %>

<%= scommit "9-5-1", "Created basic errors package and linked it in." %>

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### Writing tests

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~~~js
Tinytest.add("Errors - collection", function(test) {
  test.equal(Errors.collection.find({}).count(), 0);
  
  Errors.throw('A new error!');
  test.equal(Errors.collection.find({}).count(), 1);
  
  Errors.collection.remove({});
});

Tinytest.addAsync("Errors - template", function(test, done) {  
  Errors.throw('A new error!');
  test.equal(Errors.collection.find({}).count(), 1);
  
  // render the template
  UI.insert(UI.render(Template.meteorErrors), document.body);
  
  Meteor.setTimeout(function() {
    test.equal(Errors.collection.find({}).count(), 0);
    done();
  }, 3500);
});
~~~
<%= caption "packages/tmeasday:errors/errors_tests.js" %>

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~~~js
Package.onTest(function(api) {
  api.use('tmeasday:errors', 'client');
  api.use(['tinytest', 'test-helpers'], 'client');  
  
  api.addFiles('errors_tests.js', 'client');
});
~~~
<%= caption "packages/tmeasday:errors/package.js" %>

<%= scommit "9-5-2", "Added tests to the package." %>

////

~~~bash
meteor test-packages tmeasday:errors
~~~
<%= caption "Terminal" %>

<%= screenshot "s7-1", "Passing all tests" %>

### Releasing the package

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~~~bash
cd packages/tmeasday:errors
meteor publish --create
~~~
<%= caption "Terminal" %>

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~~~bash
rm -r packages/errors
meteor add tmeasday:errors
~~~
<%= caption "Terminal (run from the top level of the app)" %>

<%= scommit "9-5-4", "Removed package from development tree." %>

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