Validate input with a component's validate()

jComponent 20 · jcomponent@20 jcomponentfrontendvalidationforms Executed with jComponent 20

A component that edits a value can validate it. Define self.validate(value) and return true (or an empty string) when the value is valid, or false (or a message) when it is not. Write the value back with self.modify(value): it also marks the component as modified and touched.

jComponent keeps these states in config (invalid, touched, modified) and as CSS classes (ui-invalid, ui-touched, ui-modified), so styling needs no code. ERRORS(path, callback) returns the invalid components below a path, which is what a form needs before it submits, and RESET(path) clears the touched and modified states.

public/index.html

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8" />
	<title>jComponent</title>
	<link rel="stylesheet" href="//cdn.componentator.com/spa.min@20.css" />
	<script src="//cdn.componentator.com/spa.min@20.js"></script>
</head>
<body>
	<style>.ui-invalid input { border: 2px solid crimson; }</style>

	<ui-component name="required" path="form.name"></ui-component>
	<ui-component name="required" path="form.email"></ui-component>

	<script>

		COMPONENT('required', function(self) {

			self.make = function() {
				self.html('<input type="text" />');
				self.find('input').on('input', function() {
					self.modify(this.value);
				});
			};

			self.validate = function(value) {
				return !!value && value.length > 2;
			};

			self.setter = function(value) {
				self.find('input').val(value || '');
			};
		});

		SET('form.name', 'Peter');
		SET('form.email', '');

	</script>

</body>
</html>

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