Deprecated: Smarty::_getTemplateId(): Implicitly marking parameter $template as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/Smarty.class.php on line 1048

Deprecated: Smarty_Internal_Data::getTemplateVars(): Implicitly marking parameter $_ptr as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/sysplugins/smarty_internal_data.php on line 193

Deprecated: Smarty_Internal_Data::_mergeVars(): Implicitly marking parameter $data as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/sysplugins/smarty_internal_data.php on line 203

Deprecated: Smarty_Internal_Template::__construct(): Implicitly marking parameter $_parent as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/sysplugins/smarty_internal_template.php on line 149

Deprecated: Smarty_Resource::source(): Implicitly marking parameter $_template as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/sysplugins/smarty_resource.php on line 175

Deprecated: Smarty_Resource::source(): Implicitly marking parameter $smarty as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/sysplugins/smarty_resource.php on line 175

Deprecated: Smarty_Resource::populate(): Implicitly marking parameter $_template as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/sysplugins/smarty_resource.php on line 199

Deprecated: Smarty_Template_Source::load(): Implicitly marking parameter $_template as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/sysplugins/smarty_template_source.php on line 158

Deprecated: Smarty_Template_Source::load(): Implicitly marking parameter $smarty as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/sysplugins/smarty_template_source.php on line 158

Deprecated: Smarty_Internal_Resource_File::populate(): Implicitly marking parameter $_template as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/sysplugins/smarty_internal_resource_file.php on line 28

Deprecated: Smarty_Internal_Resource_File::buildFilepath(): Implicitly marking parameter $_template as nullable is deprecated, the explicit nullable type must be used instead in /export/sd206/www/jp/r/e/gmoserver/1/0/sd0297310/charobo.com/libs/sysplugins/smarty_internal_resource_file.php on line 101
アロー関数とは|初心者から学ぶReact.js入門

アロー関数とは

アロー関数は、JavaScriptの機能の1つで、関数を簡潔に記述できるものです。React.jsでは、アロー関数を使うことで、コードを簡潔に記述したり、パフォーマンスを向上させたりする効果があります。

アロー関数を使わない場合
const onClickHandler = function() {
	console.log("Hello World!");
};
アロー関数を使う場合
const onClickHandler = () => {
	console.log("Hello World!");
};

React.jsで書くコードの例も見てみましょう。

アロー関数を使わない場合
function hello(name) {
	return (
		<div>
			こんにちは、{name}さん!
		</div>
	);
}
アロー関数を使う場合
const hello = (name) => (
	<div>
		こんにちは、{name}さん!
	</div>
);