Marty Pitt Marty Pitt - 1 month ago 6
Javascript Question

Customizing the template within a Directive

I have a form that is using markup from Bootstrap, like the following:

<form class="form-horizontal">
<fieldset>
<legend>Legend text</legend>
<div class="control-group">
<label class="control-label" for="nameInput">Name</label>
<div class="controls">
<input type="text" class="input-xlarge" id="nameInput">
<p class="help-block">Supporting help text</p>
</div>
</div>
</fieldset>
</form>


There's a lot of boilerplate code in there, that I'd like to reduce to a new directive - form-input, like follows:

<form-input label="Name" form-id="nameInput"></form-input>


generates:

<div class="control-group">
<label class="control-label" for="nameInput">Name</label>
<div class="controls">
<input type="text" class="input-xlarge" id="nameInput">
</div>
</div>


I have this much working via a simple template.

angular.module('formComponents', [])
.directive('formInput', function() {
return {
restrict: 'E',
scope: {
label: 'bind',
formId: 'bind'
},
template: '<div class="control-group">' +
'<label class="control-label" for="{{formId}}">{{label}}</label>' +
'<div class="controls">' +
'<input type="text" class="input-xlarge" id="{{formId}}" name="{{formId}}">' +
'</div>' +
'</div>'

}
})


However it's when I come to add in more advanced functionality that I'm getting stuck.

How can I support default values in the template?



I'd like to expose the "type" parameter as an optional attribute on my directive, eg:

<form-input label="Password" form-id="password" type="password"/></form-input>
<form-input label="Email address" form-id="emailAddress" type="email" /></form-input>


However, if nothing is specified, I'd like to default to
"text"
. How can I support this?

How can I customize the template based on the presence / absence of attributes?



I'd also like to be able to support the "required" attribute, if it's present.
Eg:

<form-input label="Email address" form-id="emailAddress" type="email" required/></form-input>


If
required
is present in the directive, I'd like to add it to the generated
<input />
in the output, and ignore it otherwise. I'm not sure how to achieve this.

I suspect these requirements may have moved beyond a simple template, and have to start using the pre-compile phases, but I'm at a loss where to start.

Answer
angular.module('formComponents', [])
  .directive('formInput', function() {
    return {
        restrict: 'E',
        compile: function(element, attrs) {
            var type = attrs.type || 'text';
            var required = attrs.hasOwnProperty('required') ? "required='required'" : "";
            var htmlText = '<div class="control-group">' +
                '<label class="control-label" for="' + attrs.formId + '">' + attrs.label + '</label>' +
                    '<div class="controls">' +
                    '<input type="' + type + '" class="input-xlarge" id="' + attrs.formId + '" name="' + attrs.formId + '" ' + required + '>' +
                    '</div>' +
                '</div>';
            element.replaceWith(htmlText);
        }
    };
})
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