Modern JavaScript Foundations

Template Literals and Tagged Templates

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LearnStep 1 of 3

Modern String Handling in JavaScript

Learning Objectives

•Master the syntax of backticks for defining flexible template literals.
•Use expression interpolation to embed dynamic values and logic in strings.
•Create clean multi-line strings without concatenation or escape characters.
•Implement tagged template functions to manipulate and sanitize template output.

Lesson Outline

LearnStep 1/3

Modern String Handling in JavaScript

Template literals, introduced in ES6, revolutionized how we work with strings in JavaScript. They use backticks (`) instead of single or double quotes.

1. Multi-line Strings

Traditionally, multi-line strings required \n or string concatenation. With template literals, the whitespace and newlines are preserved exactly as written:

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2. Expression Interpolation

You can embed any valid JavaScript expression inside a template literal using ${expression}. This is much more readable than concatenation.

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3. Tagged Templates

Tagged templates allow you to call a function to process a template literal. The function receives an array of string literals and the evaluated expressions as arguments.

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4. Use Case: SQL Builders

Tagged templates are powerful for creating Domain Specific Languages (DSLs). A common use case is a SQL tag that automatically escapes inputs to prevent SQL injection.

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