Skip to main content
Using Deno in production at your company? Earn free Deno merch.
Give us feedback
Module

std/html/entities.ts

Deno standard library
Go to Latest
File
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** Object structure for a list of HTML entities. */export type EntityList = Record<string, string>;
const rawToEntityEntries = [ ["&", "&amp;"], ["<", "&lt;"], [">", "&gt;"], ['"', "&quot;"], ["'", "&#39;"],] as const;
const defaultEntityList: EntityList = Object.fromEntries([ ...rawToEntityEntries.map(([raw, entity]) => [entity, raw]), ["&apos;", "'"], ["&nbsp;", "\xa0"],]);
const rawToEntity = new Map<string, string>(rawToEntityEntries);
const rawRe = new RegExp(`[${[...rawToEntity.keys()].join("")}]`, "g");
/** * Escapes text for safe interpolation into HTML text content and quoted attributes. * * @example * ```ts * import { escape } from "https://deno.land/std@$STD_VERSION/html/entities.ts"; * * escape("<>'&AA"); // "&lt;&gt;&#39;&amp;AA" * * // Characters that don't need to be escaped will be left alone, * // even if named HTML entities exist for them. * escape("þð"); // "þð" * ``` */export function escape(str: string): string { return str.replaceAll(rawRe, (m) => rawToEntity.get(m)!);}
/** Options for {@linkcode unescape}. */export type UnescapeOptions = { entityList: EntityList };
const defaultUnescapeOptions: UnescapeOptions = { entityList: defaultEntityList,};
const MAX_CODE_POINT = 0x10ffff;
const RX_DEC_ENTITY = /&#([0-9]+);/g;const RX_HEX_ENTITY = /&#x(\p{AHex}+);/gu;
const entityListRegexCache = new WeakMap<EntityList, RegExp>();
/** * Unescapes HTML entities in text. * * @example * ```ts * import { unescape } from "https://deno.land/std@$STD_VERSION/html/entities.ts"; * * // Default options (only handles &<>'" and numeric entities) * unescape("&lt;&gt;&apos;&amp;&#65;&#x41;"); // "<>'&AA" * unescape("&thorn;&eth;"); // "&thorn;&eth;" * * // Using the full named entity list from the HTML spec (~47K un-minified) * import entityList from "https://deno.land/std@$STD_VERSION/html/named_entity_list.json" with { type: "json" }; * * unescape("&thorn;&eth;", { entityList }); // "þð" * ``` */export function unescape( str: string, options: Partial<UnescapeOptions> = {},): string { const { entityList } = { ...defaultUnescapeOptions, ...options };
let entityRe = entityListRegexCache.get(entityList);
if (!entityRe) { entityRe = new RegExp( `(${ Object.keys(entityList) .sort((a, b) => b.length - a.length) .join("|") })`, "g", );
entityListRegexCache.set(entityList, entityRe); }
return str .replaceAll(entityRe, (m) => entityList[m]!) .replaceAll(RX_DEC_ENTITY, (_, dec) => codePointStrToChar(dec, 10)) .replaceAll(RX_HEX_ENTITY, (_, hex) => codePointStrToChar(hex, 16));}
function codePointStrToChar(codePointStr: string, radix: number) { const codePoint = parseInt(codePointStr, radix);
return codePoint > MAX_CODE_POINT ? "�" : String.fromCodePoint(codePoint);}