svelte-trace/dist/processors/head_processor.js

svelte-trace is a Svelte 5 preprocessor that enables 'click-to-open VS Code' functionality by adding metadata to HTML elements.

import MagicString from "magic-string";
import { readFileSync, existsSync } from "fs";
import { join } from "path";
import { getVSCodeBridgeAssetsPath } from "../utils/path_utility.js";
/**
 * Generates head injection content by reading files from assets directory
 */
function generateHeadContent() {
    const assetsPath = getVSCodeBridgeAssetsPath();
    const injectionContent = [];
    try {
        // Inject CSS file if it exists
        const cssPath = join(assetsPath, "vscode_bridge.css");
        if (existsSync(cssPath)) {
            const cssContent = readFileSync(cssPath, "utf-8");
            injectionContent.push(`  <style data-svelte-trace-open-in-code>\n${cssContent}\n  </style>`);
        }
        // Inject JS file as inline script
        const jsPath = join(assetsPath, "vscode_bridge.js");
        if (existsSync(jsPath)) {
            const jsContent = readFileSync(jsPath, "utf-8");
            injectionContent.push(`  <script data-svelte-trace-open-in-code>\n${jsContent}\n  </script>`);
        }
        return injectionContent.join("\n");
    }
    catch (error) {
        console.warn("⚠️ Failed to read VS Code bridge assets:", error.message);
        return "";
    }
}
/**
 * Finds svelte:head element in AST
 */
function findSvelteHead(ast) {
    let svelteHeadNode = null;
    const walk = (node) => {
        if (node.type === "SvelteHead") {
            svelteHeadNode = node;
            return;
        }
        if (Array.isArray(node.children)) {
            node.children.forEach(walk);
        }
        if (node.fragment) {
            walk(node.fragment);
        }
        if (Array.isArray(node.nodes)) {
            node.nodes.forEach(walk);
        }
    };
    if (ast.fragment?.nodes) {
        ast.fragment.nodes.forEach(walk);
    }
    return svelteHeadNode;
}
/**
 * Injects content into svelte:head or creates one if it doesn't exist
 */
export function injectIntoHead(content, ast) {
    const magicString = new MagicString(content);
    const headContent = generateHeadContent();
    if (!headContent)
        return content;
    const svelteHead = findSvelteHead(ast);
    const injectionMarker = "<!-- svelte-trace-injection -->";
    // Prevent duplicate injection
    if (content.includes(injectionMarker))
        return content;
    // Inject before </svelte:head>
    if (svelteHead) {
        const closingTagStart = content.indexOf("</svelte:head>", svelteHead.start);
        if (closingTagStart !== -1) {
            magicString.appendLeft(closingTagStart, `${injectionMarker}\n${headContent}\n`);
        }
    }
    // Create new <svelte:head> block
    else {
        const headSection = `<svelte:head>\n${injectionMarker}\n${headContent}\n</svelte:head>\n\n`;
        let insertionPoint = 0;
        if (ast.fragment?.nodes) {
            for (const node of ast.fragment.nodes) {
                if ((node.type === "RegularElement" || node.type === "SvelteElement") &&
                    (node.name === "script" || node.name === "style")) {
                    insertionPoint = node.end;
                }
                else {
                    break;
                }
            }
        }
        magicString.appendLeft(insertionPoint, headSection);
    }
    return magicString.toString();
}