Note: While this project is generally in working order, it is no longer being actively maintained. If you would like to maintain this project, please create an issue.

About

Build production-ready, reactive forms in minutes. Even complex workflows can be achieved with just a few lines of code.

Facts

• Low-complexity architecture.
• Easy development using template helpers and reusable custom components.
• Built with Meteor's standard Template API for maximum compatibility.
• Uses SimpleSchemas for reactive validation, if provided.

Overview

This package supports two types of reusable form components:

• Elements
• Form Blocks

While Elements represent single form fields, Form Blocks are containers that control workflow and handle submission. Each type has its own set of reactive states, used to control the experience, workflow, and functionality of a given form through template helpers.

Any compatible template can be transformed into one of the above components using the provided API--and either type of component be use used standalone. But, as you'll see, the real power comes from using the two types of components together.

Create a component by registering a normal Meteor template.

ReactiveForms.createElement({
  template: 'basicInput',
  validationEvent: 'keyup'
});

Reuse the component anywhere--each instance is self-contained.

{{> basicInput schema=schema field='firstName'}}
{{> basicInput schema=schema field='lastName'}}
{{> basicInput schema=schema field='email'}}

Examples

View the Live Example

Built with Bootstrap 3 and the sacha:spin package, it demonstrates how flexible and extensible this package is.

View a Package User's Example

One of the package users, Darek Miskiewicz, has put together a great example in the form of a GitHub repo that you might prefer over the live example.

Install

meteor add templates:forms

This package works on the client-side only.

Usage

1. Provide a schema and an action function.

Define these in a parent template, or in global helpers.

Template['testForm'].helpers({
  schema: function () {
    return new SimpleSchema({
      testField: {
        type: String,
        max: 3,
        instructions: "Enter a value!"
      }
    });
  },
  action: function () {
    return function (els, callbacks, changed) {
      console.log("[forms] Action running!");
      console.log("[forms] Form data!", this);
      console.log("[forms] HTML elements with `.reactive-element` class!", els);
      console.log("[forms] Callbacks!", callbacks);
      console.log("[forms] Changed fields!", changed);
      callbacks.success(); // Display success message.
      callbacks.reset();   // Run each Element's custom `reset` function to clear the form.
    };
  }
});

The action function runs when the form is submitted. It takes three params, as shown above:

• els
  • This contains any HTML elements in the Form Block with class .reactive-element.
  • You may use this to retrieve data and save it to the database.
  • You can also use this to clear values after the form has successfully been submitted.
• callbacks
  • This contains two methods to trigger the form's state, and one method for resetting the form.
  • Running callbacks.success() sets success.
  • Running callbacks.failed() sets failed.
  • Running callbacks.reset() runs the custom reset function for each Element in the Form Block and clears Form Block state except for success and failed states and related messages. This allows users to see any available feedback even if the form is reset.
    • To clear all states and messages, use callbacks.reset(true).
  • The form's {{loading}} state (see below) will run from the time you submit to the time you call one of these.
• changed
  • If you passed in initial data, this contains an object with only the fields that have changed. If you didn't, this is undefined.
  • This is useful for figuring out what fields to use in an update query.

Retrieve Form Values with this

All validated form values are available with no extra work:

// Inside the action function...
console.log(this); // Returns {testField: "xxx"}

Data from Elements passed into the action function is guaranteed to be valid, considering:

• You provided an adequate schema.
• You used ReactiveForms Elements.
• You specified the correct schema field for each Element (see basicInput in the next example).

Hopefully, this satisfies your needs.

2. Add ReactiveForms components.

The basicFormBlock and basicInput templates are included with this package.

Connect Elements to the schema in a surrounding Form Block using the field property.

<!-- Wrapped input with form-wide schema -->
<template name="testForm">
  {{#basicFormBlock schema=schema action=action}}
    {{> basicInput field='testField'}}
  {{/basicFormBlock}}
</template>

See the templates folder to view the code.

3. Register the ReactiveForms components if needed.

This is where you configure the components.

ReactiveForms.createFormBlock({
  template: 'basicFormBlock',
  submitType: 'normal'
});

ReactiveForms.createElement({
  template: 'basicInput',
  validationEvent: 'keyup',
  reset: function (el) {
    $(el).val('');
  }
});

You only need to register a given component once.

Each time a component is rendered, it will have a unique context. Elements inside a Form Block will always be connected to the instance of the Form Block that contains them.

API

ReactiveForms has only two API endpoints.

Add any custom template that satisfies the basic requirements (outlined below), and you're ready to go!

ReactiveForms.createElement()

Create a ReactiveForms Element from a compatible template.

ReactiveForms.createElement({
  template: 'basicInput',
  validationEvent: 'keyup', // Can also be an array of events as of 1.13.0!
  validationValue: function (el, clean, template) {
    // This is an optional method that lets you hook into the validation event
    // and return a custom value to validate with.

    // Shown below is the ReactiveForms default. Clearly, this won't work in the case
    // of a multi-select form, but you could get those values and put them in an array.

    // The `clean` argument comes from SimpleSchema, but has been wrapped--
    // it now takes and returns just a value, not an object.
    console.log('Specifying my own validation value!');
    value = $(el).val();
    return clean(value);
  },
  reset: function (el) {
    $(el).val('');
  }
});

Other available options for createElement:

• validationSelector allows specifying a custom selector for the element instead of .reactive-element.
• passThroughData relates to how the element handles reactive initial data. If this is set to true, changes in the underlying data will be accepted automatically without informing the user.
  • This is useful when an element offers a set of options that you'd like to keep transparently up-to-date in real-time.
• created, rendered, and destroyed callbacks--these are safe equivalents to the normal Meteor template callbacks.

Element template requirements

• Template must contain one HTML element, for example <input>.
• The HTML element must:
  • Have the reactive-element class (or a custom selector you specify using validationSelector).
  • Support the validationEvent type(s) you specify in createElement options.

You can also put the reactive-element class on a container in the Element to delegate the event.

Here's an example of a ReactiveForms Element template.

<template name="basicInput">
  <strong>{{label}}</strong>
  <br>
  <input placeholder={{instructions}} class="reactive-element" value={{value}}>
  {{#if submitted}}
    {{#if errorMessage}}<p class="error-message">{{errorMessage}}</p>{{/if}}
  {{/if}}
</template>

Elements can be used standalone, with a SimpleSchema specified, like this:

{{> basicInput schema=schema field='testField'}}

However, Elements are usually used within a Form Block helper, where they transparently integrate with the parent form component.

{{#basicFormBlock schema=schema action=action}}
  {{> basicInput field='testField'}}
{{/basicFormBlock}}

Here's what changes when this happens:

• Elements use the form-level schema--the field property on the Element specifies which field in the form's schema to use.
• An Element that fails validation will prevent the form from submitting.
• Elements get access to form-level state, enabling helpers like {{loading}}.
• Element values that pass validation are stored in form-level data context.

Element template helpers

Element templates have access to the following local helpers:

• {{value}}
  • The last value of this Element that was able to pass validation.
  • Useful with some form components, such as a toggle button.
  • If you specified a data object on the form or Element, this will initially hold the value associated with the relevant field in that object.
• {{originalValue}} (when initial data)
  • This contains the original value from initial data for this field.
• {{uniqueValue}} (when initial data)
  • This is true if the Element's current value differs from the original value, or false if it's the same.
  • Use this to show users what fields they've changed and what fields they haven't.
• {{valid}}
  • Use this to show validation state on the Element, for example a check mark.
  • Initial data passed into the Element is validated on rendered.
  • Defaults to true if no schema is provided.
• {{changed}} (inverse {{unchanged}})
  • This is true once the Element's value has successfully changed.
  • Use this to show or hide things until the first validated value change is made.
  • Initial data passed into the Element doesn't trigger changed.
• {{isChild}}
  • This is true if the Element is wrapped in a Form Block, or false if it's not.
  • Use this to show or hide things regardless of what a parent Form Block's state is--for example, some different formatting.

These helpers are available when a SimpleSchema is being used:

• {{label}}
  • From the label field in your SimpleSchema for this Element's field.
  • Use this as the title for your Element, for example "First Name".
• {{instructions}}
  • A field we extended SimpleSchema with for this package.
  • Good for usability, use this as the placeholder message or an example value.
• {{errorMessage}}
  • A reactive error message for this field, using messages provided by SimpleSchema.

While inside a Form Block, these form-level helpers will be available:

• {{submitted}} (inverse {{unsubmitted}})
  • Lets us know if a parent ReactiveForms Form Block has been submitted yet.
  • Use this to wrap {{errorMessage}} to delay showing Element invalidations until submit.
• {{loading}}
  • Lets us know if a form action is currently running.
  • Use this to disable changes to an Element while the submit action is running.
• {{success}}
  • This is true if a form action was successful.
  • Use this to hide things in the Element after submission.

All the form-level helpers will be false when an Element is running standalone. However, you can override specific properties on an Element when you invoke it:

<!-- The `basicInput` example will now show its error messages when standalone -->
{{> basicInput schema=schema field='testField' submitted=true}}

Using nested Elements for cleaner code

As you build out your elements, you may start to feel like abstracting some common code.

Well, it only takes two steps:

1. Create a partial Element template, but without the usual .reactive-element HTML element inside. You can use all the usual Element template helpers.

2. Register the template using ReactiveForms.createElement(), but don't include the usual validationEvent field.

Here are examples of two types of possible nested elements:

Separate templates for labels and error messages.

<template name="bootstrapLabel">
  <label class="control-label">
    {{#if schema.label}}
      {{schema.label}}
    {{else}}
      {{field}}
    {{/if}}
  </label>
</template>

<template name="bootstrapErrorMsg">
  <p class="help-block">
    {{#if ../valid}}
      {{instructions}}
    {{else}}
      {{errorMessage}}
    {{/if}}
  </p>
</template>

<template name="bootstrapInput">
  <div class="form-group  {{#unless valid}}has-error{{/unless}}">
    {{> bootstrapLabel}}
    <input name="{{field}}" class="form-control reactive-element" value="{{value}}">
    {{> bootstrapErrorMsg}}
  </div>
</template>

Wrapper template for Elements (use as a block helper).

<!-- Block helper to wrap any Elements -->
<template name="myElementContainer">
  <div>
    <label>{{label}}</label>
    <br>
    {{> UI.contentBlock}}
    <!-- Show error if submitted but not successful -->
    {{#if submitted}}
      {{#if errorMessage}}<p class="error-message">{{errorMessage}}</p>{{/if}}
    {{/if}}
  </div>
</template>

<!-- Element template -->
<template name="myInputElement">
  <input placeholder={{schema.instructions}} class="reactive-element" value={{value}}>
</template>

<!-- Here's a form using all the above components -->
<template name="myLeadGenForm">
  {{#defaultFormBlock action=action schema=schema data=data}}
    {{#if success}}
      <p>Success! Form submitted.</p>
    {{else}}
      {{#myElementContainer field='firstName'}}
        {{> myInputElement field='firstName'}}
      {{/myElementContainer}}

      {{#myElementContainer field='lastName'}}
        {{> myInputElement field='lastName'}}
      {{/myElementContainer}}

      {{#myElementContainer field='phoneNumber'}}
        {{> myInputElement field='phoneNumber'}}
      {{/myElementContainer}}
    {{/if}}
    <hr>
    <button type="submit">Submit</button>
  {{/defaultFormBlock}}
</template>

Of course the above component templates need to be registered with ReactiveForms to work.

Highlights

When running standalone (without being wrapped in a Form Block) you'll put the schema on the Element's template invocation. You can also override the other form-level helpers on Elements this way.

To force an element to run in standalone mode, you can specify standalone=true in the template's invocation.

Be sure to add the reactive-element class to your Element so that it's selected when the form action is run.

Partial element templates can be used to abstract out common code. You can even create element block templates to wrap your elements.

ReactiveForms.createFormBlock()

Create a ReactiveForms Form Block from a compatible template.

ReactiveForms.createFormBlock({
  template: 'basicFormBlock',
  submitType: 'normal' // or 'enterKey', which captures that event in the form
});

Form Block template requirements

• Template code must be wrapped in a form tag.
• Template must contain UI.contentBlock with the proper fields (as below).

Here's an example of a ReactiveForms Form Block template.

<template name="basicFormBlock">
  <form>

    <!--
      Note:

      Use this `UI.contentBlock` exactly as it is here, in every Form Block template.

      There are two fields.

      1. `data`:    This allows you to pass default values into the form. If you'll
                    never use the form for updating existing data, you can leave it
                    out and nothing will break.

      2. `context`: This field is required. ReactiveForms takes care of the value
                    automatically.
    -->

    {{> UI.contentBlock data=data context=context}}

    <!-- The below helpers represent exclusive states,
      meaning they never appear at the same time -->

    <p>
      <button type="submit">Submit</button>
      <span>
        {{#if loading}}
          Loading...
        {{/if}}

        {{#if invalid}}
          Can't submit! There are {{invalidCount}} invalid fields!
        {{/if}}

        {{#if failed}}
          <strong>{{#if failedMessage}}{{failedMessage}}{{else}}Unable to submit the form.{{/if}}</strong>
        {{/if}}

        {{#if success}}
          <strong>{{#if successMessage}}{{successMessage}}{{else}}Saved!{{/if}}</strong>
        {{/if}}
      </span>
    </p>

  </form>
</template>

Form Blocks can technically be used standalone, with normal, non-reactive form elements like inputs and check boxes. The form's action function, which runs on submit, always receives an array containing the HTML elements inside the form with the .reactive-element class.

However, we strongly recommend using ReactiveForms Elements inside a Form Block, which are reactively validated with SimpleSchema:

{{#basicFormBlock schema=schema action=action}}
  {{> basicInput field='firstName'}}
  {{> basicInput field='lastName'}}
  {{> basicInput field='email'}}
{{/basicFormBlock}}

If you do this, you can trust that the data passed to your action function is already valid. All you'll need to do then is get the data from the form elements and save it somewhere!

Form Block template helpers

Form Block templates have access to the following helpers:

• {{invalid}}
  • After a submission, this is true if any ReactiveForms Element in the Form Block is invalid.
  • As soon as all Elements become valid, it changes back to false.
  • Use this to show a form-level error message after submission.
• {{invalidCount}}
  • This shows the number of currently invalid ReactiveForms Elements in the Form Block.
  • As Elements become valid, the number adjusts reactively.
• {{changed}} (inverse {{unchanged}})
  • This is true if any valid value change has been made in the Form Block since it was rendered.
  • Initial data validation doesn't trigger changed, and neither do duplicate values.
  • If changed is triggered after success, it resets submitted and success to false.
• {{submitted}} (inverse {{unsubmitted}})
  • This is true if the form has ever been submitted.
  • Submission requires all form Elements to be valid.
• {{loading}}
  • Lets us know if a form action is currently running.
  • Use this to show a spinner or other loading indicator.
• {{failed}}
  • This is true if the last attempt to run the form action failed.
• {{failedMessage}}
  • This would display "1 item failed!" in the case of callbacks.failed('1 item failed!').
• {{success}}
  • This is true if the last attempt to run the form action was a success.
  • Use this to hide Elements or otherwise end the form's session.
• {{successMessage}}
  • This would display "Thank you!" in the case of callbacks.success('Thank you!').

Highlights

A Form Block's failed, success, invalid, and loading states are mutually exclusive.

When a Form Block's success state is true, setting its changed state to true will cause both its success and submitted states to become false. This makes it possible for users to edit and submit a given form many times in one session--just keep the editable Elements accessible in the UI after the first success (or provide a button that triggers the changed state).

ReactiveForms Elements inside a Form Block affect the form's validity. They are reactively validated with SimpleSchema at the form-level, thanks to a shared schema context.

Working With Reactive Form Data

Due to the real-time nature of Meteor, one can only assume that while editing some existing data in a form, the original data might change before the edited work is submitted.

When data is changed remotely during a form session, there are three obvious ways to handle the experience:

1. Ignore the change and let the user submit their new form.
2. Patch in the changes mid-session without any real prompt.
3. Notify the user of remote changes and give them the opportunity to view and import those changes into the current session.

This package supports all three of the above options, but special care has been taken to ensure a good experience in the case of #3.

Here's a working example of how easy it is to present a user with the option to accept or ignore remote changes.

This is purely focused on text inputs--the other types of form elements will have different experiences and constraints.

<template name="inputElement">
  <input type={{type}} placeholder={{schema.instructions}} class="reactive-element" value={{value}}>
  {{#if remoteValueChange}}
    <p style="color:black">
      This field has been updated remotely. Load the latest
      <span title={{newRemoteValue}}>changes</span>?
      <button class="accept-changes">Load</button> <button class="ignore-changes">Ignore</button>
    </p>
  {{/if}}
</template>

Template['inputElement'].events({
  'click .accept-changes': function (e, t) {
    e.preventDefault();
    var inst = Template.instance();
    inst[ReactiveForms.namespace].acceptValueChange();
  },
  'click .ignore-changes': function (e, t) {
    e.preventDefault();
    var inst = Template.instance();
    inst[ReactiveForms.namespace].ignoreValueChange();
  }
});

As you can see, we have access to the following template helpers:

• {{remoteValueChange}}
  • This is true if this Element's data has changed elsewhere during the current session. It resets every time changes are accepted or ignored.
  • Use this to toggle the message.
• {{newRemoteValue}}
  • This contains the actual value of the changed data. In our example, we put it in a name attribute, but it could be used for a tooltip or anything else.

We can control how we deal with remote changes using these template instance methods:

• acceptValueChange()
  • A method that copies the changed data into the current form data context (and thus into the Elements, depending on your configuration).
• ignoreValueChange()
  • A method that resets remoteValueChange to false.

For more fine-grained control over how your form handles remote data changes, specify an onDataChange hook via a template helper (just like schema, action, and data):

Template['testForm'].helpers({
  onDataChange: function() {
    return function(oldData, newData) {
      if (!_.isEqual(oldData, newData)) {

        // Use one or more of the below methods.
        // Usually, you should only need `this.refresh()`.
        // Create an issue if you need something else here.

        // Reset the form (equivalent to `callbacks.reset()` in the action function).
        this.reset(true);

        // Refresh unchanged Elements to reflect new data.
        // Optionally: `this.refresh('dot.notation', customValue)`.
        this.refresh();

        // This sets the form's `changed` state to `true`.
        this.changed();

      }
    };
  }
});

This hook allows you to update your entire form during remote data changes without needing to use passThroughData on individual elements.

Other Forms Packages

Here's the low-down on other Meteor forms packages and how they compare to this one.

AutoForm

While AutoForm strives to offer every option under the sun, templates:forms is minimalist in nature--it gives you what you need to build your own stuff, and doesn't make too many assumptions!

• AutoForm is a much heavier package than templates:forms, as it aims to do much more.
• Its API is significantly more verbose.
• It has many features and options--perhaps too many, depending on your taste.
  • AutoForm will auto-generate HTML forms for you off your schema.
  • AutoForm integrates with Collection2.
  • It will fully handle form submission for you, including database inserts.
• It also validates with SimpleSchema.
• It comes from the pre-1.0 era of Meteor, and isn't fully optimized for the new Template API.
  • In comparison, templates:forms always keeps things self-contained in template instances.
• It has some nice plugins created by community members.

Know of another good forms package? Fork this repo, add it here, and create a PR!

Contributors

• Jon James

Special thanks to steph643 for significant testing and review.

My goal with this package is to keep it simple and flexible, similar to core packages.

As such, it may already have everything it needs.

Please create issues to discuss feature contributions before creating a pull request.