Template engines and data rendering techniques in JavaScript-JS Tutorial-php.cn

Template engines and data rendering techniques in JavaScript

王林

Release： 2023-06-16 13:40:37

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With the popularity of web applications, JavaScript has become the core of front-end technology. JavaScript can add interactivity and complexity to dynamic web pages and ease developers' workload through template engines and data rendering techniques. In this article, we will learn more about template engines and data rendering techniques in JavaScript.

1. Template engine

The template engine is a tool used to generate documents in HTML, XML or other formats. In JavaScript, the most commonly used template engines are Mustache and Handlebars. The two template engines are very similar, but Handlebars is more flexible than Mustache.

Mustache

Mustache is a simple but powerful template engine. It can render data by using placeholders and generate HTML code. Placeholders are enclosed in double curly braces, such as {{name}}. To use Mustache, you need to download Mustache.js first and introduce it in the HTML document.

The following is a simple Mustache example:

<!DOCTYPE html>
<html>
<head>
    <script src="mustache.js"></script>
</head>
<body>
    <div id="output"></div>

    <script>
        var data = {
            "name": "John",
            "age": 30
        };

        var template = "My name is {{name}} and I am {{age}} years old.";

        var output = document.getElementById("output");
        output.innerHTML = Mustache.render(template, data);
    </script>
</body>
</html>

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In this example, we define a data object data and a Mustache template template. Then, the data object is rendered into the template through Mustache's render() method, the HTML code is generated and inserted into the output element in the page.

Handlebars

Handlebars are more flexible than Mustache. It has the same templates and data structures, but you can also define helper functions and blocks to make the templates more readable and easier to maintain. Handlebars can also improve performance by precompiling templates.

The following is a simple Handlebars example:

<!DOCTYPE html>
<html>
<head>
    <script src="handlebars.js"></script>
</head>
<body>
    <div id="output"></div>

    <script id="template" type="text/x-handlebars-template">
        My name is {{name}} and I am {{age}} years old.
    </script>

    <script>
        var data = {
            "name": "John",
            "age": 30
        };

        var template = document.getElementById("template").innerHTML;

        var compiledTemplate = Handlebars.compile(template);
        var output = document.getElementById("output");

        output.innerHTML = compiledTemplate(data);
    </script>
</body>
</html>

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In this example, we define a Handlebars template and a data object data. We first need to get the template from the HTML document and pass it to the Handlebars.compile() method to get an executable template. We then pass the data object to the compiled template and insert the result into the output element in the page.

2. Data Rendering Techniques

In addition to using template engines, there are some other JavaScript data rendering techniques that can help us better present data.

forEach() method

JavaScript’s forEach() method can be used to iterate over each element in an array and perform the same operation on it. For example, we can use the forEach() method to render a set of data into a table on the page.

The following is a simple example of the forEach() method:

<!DOCTYPE html>
<html>
<head>
</head>
<body>
    <table>
        <thead>
            <tr>
                <th>Name</th>
                <th>Age</th>
            </tr>
        </thead>
        <tbody id="output"></tbody>
    </table>

    <script>
        var data = [
            { "name": "John", "age": 30 },
            { "name": "Jane", "age": 25 },
            { "name": "Bob", "age": 35 }
        ];

        var output = document.getElementById("output");

        data.forEach(function (item) {
            var row = document.createElement("tr");
            var nameCell = document.createElement("td");
            nameCell.innerText = item.name;
            row.appendChild(nameCell);

            var ageCell = document.createElement("td");
            ageCell.innerText = item.age;
            row.appendChild(ageCell);

            output.appendChild(row);
        });
    </script>
</body>
</html>

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In this example, we define a data object data and a table element. We use the forEach() method to iterate through the data object and create a new row and two cells for each data item. Then, insert the row into the tbody element in the table.

Template strings

Introduced in ES6, template strings are a new syntax for creating multi-line strings and inserting variables. Using template strings makes it easier to render data into the page.

The following is a simple template string example:

<!DOCTYPE html>
<html>
<head>
</head>
<body>
    <div id="output"></div>

    <script>
        var data = {
            "name": "John",
            "age": 30
        };

        var output = document.getElementById("output");
        output.innerHTML = `
            My name is ${data.name} and I am ${data.age} years old.
        `;
    </script>
</body>
</html>

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In this example, we define a data object data and an output element. We use the template string to create a multiline string containing the data and insert it into the output element.

Conclusion

In JavaScript, template engines and data rendering techniques can enable us to present data more efficiently, reducing coding time and error rates. Mustache and Handlebars are two common template engines, while the forEach() method and template strings are other useful data rendering techniques. These technologies can not only help us improve development efficiency, but also make web pages easier to maintain and upgrade.

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