ng-dynaform

NgDynaform

A Dynamic Form Builder for Angular, with built in model mapper.

• Define forms with metadata, or build directly from models

• Combine metadata with models to populate form values

• Group related fields in containers, to any level of nesting

• Use repeating containers to model complex arrays

• Take advantage of terse metadata, and sensible defaults

Basic Usage

Import the Dynaform module.

import { NgModule } from '@angular/core';

...

import { DynaformModule } from './dynaform/dynaform.module';
...

@NgModule({
	imports: [
		...
		DynaformModule
		...
	]
    ...
})
export class AppModule { }

In any component where you want to generate a form, import andthen inject the DynaformService.

import { Component } from '@angular/core';
import { FormGroup } from '@angular/forms';
import { DynaformService } from './dynaform'; // Paths may vary

@Component({
	selector: 'app-root',
	templateUrl: './app.component.html',
	styleUrls: ['./app.component.scss']
})
export class AppComponent implements OnInit {

	form: FormGroup;
	meta: StringMap<any>;

    constructor(private dynaform: DynaformService) {
    }

Build the form from your model, your metadata, or a combination of the two.

ngOnInit() {

	const model = { firstName: 'Olly', lastName: 'October', country: 'France' };
    const meta = {
        country: { type: 'select', options: ['France', 'Germany', 'Norway', 'Sweden'] }
    }
    
    // Build FormGroup and Modeled Metadata
	const { form, modeledMeta } = this.dynaform.build(model, meta);

}

Build strategies

Dynaform supports two build strategies: MODELFISRT and METAFIRST (the default)

MODELFIRST generates a form from the supplied model, and by default will ignore any metadata points that don't occur in the model.

METAFIRST generates a form from the supplied metadata, and by default will ignore any data in the model that doesn't have a corresponding metadata entry.

You can set the build strategy by calling setBuildStrategy

this.dynaform.setBuildStrategy('MODELFIRST');

The behaviour of the MODELFIRST build strategy can be further modified by supplying true as the third parameter to dynaform.build, where true means "create extra fields from metadata, even when they don't occur ion the model". It's useful when the model might be incomplete.

// Build FormGroup and Modeled Metadata, creating fields for any points mentioned in 
// the metadata that don't occur in the model
const { form, modeledMeta } = this.dynaform.build(model, meta);

Callbacks

• Callbacks allow events inside a form to trigger functions in the host component.
• Callbacks can be attached to buttons, and to the change handler of any field.
• Callbacks are identified by a string, which maps them to a function in the host component.

// Register callbacks (probably in ngOnInit)
this.dynaform.register({
	'SAYHELLO': this.sayHello,
	'SAYCHEESE': this.sayCheese
}, this);

Then later in the component...

handleCallback(fnId) {
	this.dynaform.call(fnId);
}

sayHello() {
	alert('HELLO');
}

sayCheese() {
	alert('CHEESE');
}

Field metadata

Common properties

All fields support the following metadata. The missing properties will be 'filled oin' by dynaform's field-specific models, allowing forms to specifiued tersely.

Property	Description	Default / Notes
name	The FormControl name	Do not set. Derived automatically from the key of the metadata object.
type	The control's type	Text
label	The controls's label	An unCamelCased and spaced version of name
value	The control's initial value	Empty string. May be set from model, overriding the default
checkedValue	Value when checked*	Checkboxes / Checkbuttons only
default	The control's default value
placeholder	Optional placeholder text
class	CSS class(es) to apply	Single class (string) or array of classes (string[])
id	CSS id to apply
disabled	Whether field is disbled	false
change	Name of function in host component to call when value changes
source	Location of data in model	Defaults to the same name and path. Used by model-mapper.
before	Ordering instruction - move before name of another control in group
after	Ordering instruction - move after name of another control in group
validators	Array of validator functions - following Angular FormControl API	[]
asyncValidators	Array of async validator functions - following Angular FormControl API	[]
valFailureMsgs	Validation failure messages - used to display appropriate message if validation fails

Available types

• Text
• Textarea
• Select
• Radio
• Checkbox
• Checkbutton
• Password
• Hidden
• Checkbox
• CheckboxGroup
• Datepicker
• Timepicker
• DropdownModifiedInput
• Multiline

'Option' field metadata

(for selects, radios, checkbutton groups, etc)

Options can be specified as an array of values, an array of [value, label] pairs, or an array of objects with the structure { value: 'VAL', label: 'My label' }. If you supply a a simple array of values, each value is used as both the value and label.

Examples

{
	firstName: {},
	lastName: {},
	telephoneNumber: {},
	country: { type: 'select', options: ['France', 'Germany', 'Italy', 'Norway'] }
}

{
	cheeseLover: { type: 'checkbox', label: 'Do you like cheese?' },
	favouriteCheese: {
		type: 'radio',
		label: 'What`s your favourite?',
		options: [
			['CHED', 'Cheddar'],
			['WENS', 'Wensleydale'],
			['BRIE', 'Brie'],
			['GORG', 'Gorgonzola']
		]
	}
}

Field-type specific metadata

TO ADD.

e.g. radio, horizontal.

Containers

Related fields can be grouped using containers. A container has it's own meta property, under which the fields it contains are defined in the usual way. Containers can even contain other containers, with no hard limit on depth, although in practice you'll probably not need to use deeply nested metadata.

cheeseMakersContract and cheeseMakersAddress are both containers...

{
	optIn: { label: 'Become a cheese maker?', type: 'checkbutton' },
	optInConfirm: { label: 'Really?', type: 'radio', options: ['Yes', 'No', 'Maybe'] },
	cheeseMakersContract: {
		label: 'Contract details',
		meta: {
			type: { label: 'Contract type' },
			startDate: { type: 'datepicker' }
      cheeseMakersAddress: {
        label: 'Address'
        meta: {
          address1: {},
          address2: {},
          city: {},
          postcode: { class: 'short-field' }
        }
      }
		}
	}
}

Container options

Property	Description	Default / Notes
name	The FormGroup name	Do not set. Derived automatically from the key of the metadata object.
label	Optional container label	Creates a heading above the container
seed	An object containing key-value pairs, used to seed metadata for all contained fields	Use when all or most fields share certain properties, e.g. to apply the same class or default
template	Optional template override	This should be an Angular TemplateRef See https://angular.io/api/core/TemplateRef

Seeding containers with shared options

TO ADD.

Repeating Containers

TO ADD.

Buttons

TO ADD.

Presentational types

TO ADD.

The built-in model mapper

TO ADD.

Programatically updating displayed form values

TO ADD.

Validation

TO ADD.