Template strings are a feature introduced in JavaScript ES6, which wraps content with backticks and supports variable interpolation and multi-line strings. 1. Use backticks to define a string such as this is a template literal; 2. Insert variables or expressions through ${} syntax such as I am ${age} years old.; 3. Naturally support multi-line text without manually adding newlines. Common scenarios include dynamically generating HTML content, multi-line string output, and simplified conditional logical stitching. Notes include avoiding injection attacks, advanced usage of tag templates, and keeping logic simple.

Template Literals is a practical feature introduced in JavaScript ES6, which makes string stitching and embedding variables more intuitive and concise. Compared with the traditional string splicing method, using template strings can improve code readability and development efficiency.

What is a template string?

Template strings use backquotes (`) to wrap the contents, rather than single or double quotes. Its biggest feature is that it supports variable interpolation and multi-line strings , which are very suitable for handling dynamic content and strings with more complex structures.

 const name = 'Alice';
console.log(`Hello, ${name}!`);
// Output: Hello, Alice!

This writing not only reduces the plus sign connections when string splicing, but also avoids the confusion caused by quotation mark nesting.

Basic syntax for template strings

The core syntax of template strings includes:

• Define a string using backticks :

  

   `This is a template literal`

• Insert variables or expressions using ${} syntax:

   const age = 25;
  `I am ${age} years old.`;

• Supports multi-line text without manually adding newlines:

   `Line one
  Line two`;

These syntax features combine to make building complex strings easier and more natural.

Common usage scenarios

1. Dynamically generate HTML content

In front-end development, it is often necessary to generate HTML strings based on data. Template strings can easily embed variables into HTML structures:

 const user = { name: 'Bob', role: 'Admin' };
const html = `<div class="user">
  <h2>${user.name}</h2>
  <p>Role: ${user.role}</p>
</div>`;

This method compares The splicing is much clearer and easier to maintain.

2. Multi-line string output

If you want to write multiple lines of strings in the traditional way, you must add them with \n or multiple strings, and the template strings are naturally supported:

 `This is line one.
This is line two.
And this is line three.`;

This is very convenient in scenarios such as debugging logs and generating explanatory texts.

3. Simplify conditional logical stitching

Sometimes we need to splice different content according to the conditions, and we can write simple expressions directly in ${} :

 const score = 85;
`Your grade is ${score >= 60 ? 'Pass' : 'Fail'}`;

Although it is not recommended to put too complicated logic in it, simple ternary operations are very suitable.

Notes and tips

• Avoid injection attacks : If you put the user input directly into the template string and insert it into the DOM, there may be XSS risks. Make sure that the content is escaped or processed safely.
• Advanced usage of tagged templates : You can customize a function to handle template strings, such as internationalization, CSS interpolation and other advanced uses.
• Keep the logic concise : Although you can write expressions in ${} , try not to put too long or too complicated logic to affect readability.

Basically that's it. Template strings may seem simple, but they are very practical in daily development, especially when you frequently operate strings. Mastering its basic usage and common patterns will allow you to write cleaner and easier to maintain code.

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