91 lines
3.9 KiB
JavaScript
91 lines
3.9 KiB
JavaScript
/**
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* @fileoverview Rule to require alternative text for images in Markdown.
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* @author Pixel998
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*/
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//-----------------------------------------------------------------------------
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// Imports
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//-----------------------------------------------------------------------------
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import { stripHtmlComments } from "../util.js";
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//-----------------------------------------------------------------------------
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// Type Definitions
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//-----------------------------------------------------------------------------
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/**
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* @import { Image, ImageReference } from "mdast";
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* @import { MarkdownRuleDefinition } from "../types.js";
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* @typedef {"altTextRequired"} RequireAltTextMessageIds
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* @typedef {[]} RequireAltTextOptions
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* @typedef {MarkdownRuleDefinition<{ RuleOptions: RequireAltTextOptions, MessageIds: RequireAltTextMessageIds }>} RequireAltTextRuleDefinition
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*/
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//-----------------------------------------------------------------------------
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// Helpers
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//-----------------------------------------------------------------------------
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const imgTagPattern = /<img(?:\s(?:[^>"']|"[^"]*"|'[^']*')*)?\/?>/giu;
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/**
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* Creates a regex to match HTML attributes
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* @param {string} name The attribute name to match
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* @returns {RegExp} Regular expression for matching the attribute
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*/
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function getHtmlAttributeRe(name) {
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return new RegExp(`\\s${name}(?:\\s*=\\s*['"]([^'"]*)['"])?`, "iu");
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}
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//-----------------------------------------------------------------------------
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// Rule Definition
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//-----------------------------------------------------------------------------
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export default /** @satisfies {RequireAltTextRuleDefinition} */ ({
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meta: {
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type: "problem",
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docs: {
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recommended: true,
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description: "Require alternative text for images",
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url: "https://github.com/eslint/markdown/blob/main/docs/rules/require-alt-text.md",
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},
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messages: {
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altTextRequired: "Alternative text for image is required.",
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},
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},
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create(context) {
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const { sourceCode } = context;
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return {
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"image, imageReference"(
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/** @type {Image | ImageReference} */ node) {
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if (node.alt.trim().length === 0) {
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context.report({
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loc: node.position,
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messageId: "altTextRequired",
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});
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}
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},
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html(node) {
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const text = stripHtmlComments(sourceCode.getText(node));
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/** @type {RegExpExecArray | null} */
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let match;
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while ((match = imgTagPattern.exec(text)) !== null) {
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const imgTag = match[0];
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const ariaHiddenMatch = imgTag.match(getHtmlAttributeRe("aria-hidden"));
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if (ariaHiddenMatch &&
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ariaHiddenMatch[1] &&
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ariaHiddenMatch[1].toLowerCase() === "true") {
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continue;
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}
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const altMatch = imgTag.match(getHtmlAttributeRe("alt"));
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if (!altMatch ||
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(altMatch[1] &&
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altMatch[1].trim().length === 0 &&
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altMatch[1].length > 0)) {
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const startOffset = // Adjust `imgTagPattern` match indices to the full source code.
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match.index + node.position.start.offset;
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const endOffset = startOffset + imgTag.length;
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context.report({
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loc: {
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start: sourceCode.getLocFromIndex(startOffset),
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end: sourceCode.getLocFromIndex(endOffset),
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},
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messageId: "altTextRequired",
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});
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}
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}
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},
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};
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},
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});
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