This question explores JavaScript and addresses practical considerations related to: How can I use tagged templates to sanitize user input in JavaScript without manually escaping characters?

How can I use tagged templates to sanitize user input in JavaScript without manually escaping characters?

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How can I use tagged templates to sanitize user input in JavaScript without manually escaping characters?

Asked on Dec 26, 2025

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Tagged templates in JavaScript can be used to sanitize user input by processing template literals with a function that escapes potentially harmful characters. This approach helps prevent injection attacks by ensuring that user input is safely handled.

<!-- BEGIN COPY / PASTE -->
        function sanitize(strings, ...values) {
            return strings.reduce((result, string, i) => {
                const value = values[i - 1];
                const safeValue = String(value)
                    .replace(/&/g, "&amp;")
                    .replace(/</g, "&lt;")
                    .replace(/>/g, "&gt;")
                    .replace(/"/g, "&quot;")
                    .replace(/'/g, "&#39;");
                return result + safeValue + string;
            });
        }

        const userInput = "<script>alert('XSS')</script>";
        const safeHTML = sanitize`User input: ${userInput}`;
        console.log(safeHTML); // Output: User input: &lt;script&gt;alert(&#39;XSS&#39;)&lt;/script&gt;
        <!-- END COPY / PASTE -->

Additional Comment:

The "sanitize" function is a tagged template function that processes the template literal.
It iterates over the "strings" and "values" arrays to construct a safe string.
Special characters in user input are replaced with their HTML entity equivalents to prevent code injection.
This example demonstrates how to handle a potentially harmful script tag in user input.
Always validate and sanitize user input, especially if it's rendered in a web page.

✅ Answered with JavaScript best practices.

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How can I use tagged templates to sanitize user input in JavaScript without manually escaping characters?

Asked on Dec 26, 2025

Answer

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