# Template literals (Template strings) — Tagged templates and escape sequences

> In normal template literals, the escape sequences in string literals are all allowed.

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## Metadata

- Canonical URL: <https://wikikv.com/k/ref-mdn-f7d113113c98e6111059>
- Knowledge kind: `reference`
- Confidence: `0.72`
- Independent verifications: `0`
- Updated: `2026-08-16T09:32:14.516536+00:00`
- Tags: `reference-seed`, `mdn`, `web`, `javascript`, `reference`, `template-literals`, `template`, `literals`, `strings`, `tagged`, `templates`, `escape`

## Provenance

- Source: <https://github.com/mdn/content/blob/d14bee540b5305ddeb93969618ba05102b648bb6/files/en-us/web/javascript/reference/template_literals/index.md>
- Source name: MDN Web Docs
- Source revision: `d14bee540b5305ddeb93969618ba05102b648bb6`
- Source license: `CC-BY-SA-2.5`
- Attribution and license details: <https://wikikv.com/licenses>

## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

In normal template literals, the escape sequences in string literals are all allowed. Any other non-well-formed escape sequence is a syntax error. This includes

\ followed by any decimal digit other than 0, or \0 followed by a decimal digit; for example \9 and \07 (which is a deprecated syntax) \x followed by fewer than two hex digits (including none); for example \xz \u not followed by { and followed by fewer than four hex digits (including none); for example \uz \u{} enclosing an invalid Unicode code point — it contains a non-hex digit, or its value is greater than 10FFFF; for example \u{110000} and \u{z}

&gt; [!NOTE] &gt; \ followed by other characters, while they may be useless since nothing is escaped, are not syntax errors.

However, this is problematic for tagged templates, which, in addition to the "cooked" literal, also have access to the raw literals (escape sequences are preserved as-is).

Tagged templates enable the embedding of arbitrary string content, where escape sequences may follow a different syntax. Consider for an example where we embed LaTeX source text in JavaScript via String.raw. We want to still be able to use LaTeX macros that start with u or x without following JavaScript syntax restrictions. Therefore, the syntax restriction of well-formed escape sequences is removed from tagged templates. The example below uses MathJax to render LaTeX in one element

However, illegal escape sequences must still be represented in the "cooked" representation. They will show up as {{jsxref("undefined")}} element in the "cooked" array

Note that the escape-sequence restriction is only dropped from _tagged_ templates, but not from _untagged_ template literals

Attribution: Adapted from MDN Web Docs under CC-BY-SA-2.5. Adaptation: WikiKV selected one documentation section, normalized formatting, retained bounded excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.