Update ES Module Shims to 1.7.3 (#188)

Author: dhh

app/assets/javascripts/es-module-shims.js

@@ -1,4 +1,4 @@
-/* ES Module Shims 1.7.2 */
+/* ES Module Shims 1.7.3 */
 (function () {
 
   const hasWindow = typeof window !== 'undefined';
@@ -596,88 +596,109 @@
     // edge doesnt execute sibling in order, so we fix this up by ensuring all previous executions are explicit dependencies
     let resolvedSource = edge && lastLoad ? `import '${lastLoad}';` : '';
 
-    if (!imports.length) {
-      resolvedSource += source;
-    }
-    else {
-      // once all deps have loaded we can inline the dependency resolution blobs
-      // and define this blob
-      let lastIndex = 0, depIndex = 0, dynamicImportEndStack = [];
-      function pushStringTo (originalIndex) {
-        while (dynamicImportEndStack[dynamicImportEndStack.length - 1] < originalIndex) {
-          const dynamicImportEnd = dynamicImportEndStack.pop();
-          resolvedSource += `${source.slice(lastIndex, dynamicImportEnd)}, ${urlJsString(load.r)}`;
-          lastIndex = dynamicImportEnd;
-        }
-        resolvedSource += source.slice(lastIndex, originalIndex);
-        lastIndex = originalIndex;
+    // once all deps have loaded we can inline the dependency resolution blobs
+    // and define this blob
+    let lastIndex = 0, depIndex = 0, dynamicImportEndStack = [];
+    function pushStringTo (originalIndex) {
+      while (dynamicImportEndStack[dynamicImportEndStack.length - 1] < originalIndex) {
+        const dynamicImportEnd = dynamicImportEndStack.pop();
+        resolvedSource += `${source.slice(lastIndex, dynamicImportEnd)}, ${urlJsString(load.r)}`;
+        lastIndex = dynamicImportEnd;
       }
-      for (const { s: start, ss: statementStart, se: statementEnd, d: dynamicImportIndex } of imports) {
-        // dependency source replacements
-        if (dynamicImportIndex === -1) {
-          let depLoad = load.d[depIndex++], blobUrl = depLoad.b, cycleShell = !blobUrl;
-          if (cycleShell) {
-            // circular shell creation
-            if (!(blobUrl = depLoad.s)) {
-              blobUrl = depLoad.s = createBlob(`export function u$_(m){${
-              depLoad.a[1].map(({ s, e }, i) => {
-                const q = depLoad.S[s] === '"' || depLoad.S[s] === "'";
-                return `e$_${i}=m${q ? `[` : '.'}${depLoad.S.slice(s, e)}${q ? `]` : ''}`;
-              }).join(',')
-            }}${
-              depLoad.a[1].length ? `let ${depLoad.a[1].map((_, i) => `e$_${i}`).join(',')};` : ''
-            }export {${
-              depLoad.a[1].map(({ s, e }, i) => `e$_${i} as ${depLoad.S.slice(s, e)}`).join(',')
-            }}\n//# sourceURL=${depLoad.r}?cycle`);
-            }
-          }
-
-          pushStringTo(start - 1);
-          resolvedSource += `/*${source.slice(start - 1, statementEnd)}*/${urlJsString(blobUrl)}`;
+      resolvedSource += source.slice(lastIndex, originalIndex);
+      lastIndex = originalIndex;
+    }
 
-          // circular shell execution
-          if (!cycleShell && depLoad.s) {
-            resolvedSource += `;import*as m$_${depIndex} from'${depLoad.b}';import{u$_ as u$_${depIndex}}from'${depLoad.s}';u$_${depIndex}(m$_${depIndex})`;
-            depLoad.s = undefined;
+    for (const { s: start, ss: statementStart, se: statementEnd, d: dynamicImportIndex } of imports) {
+      // dependency source replacements
+      if (dynamicImportIndex === -1) {
+        let depLoad = load.d[depIndex++], blobUrl = depLoad.b, cycleShell = !blobUrl;
+        if (cycleShell) {
+          // circular shell creation
+          if (!(blobUrl = depLoad.s)) {
+            blobUrl = depLoad.s = createBlob(`export function u$_(m){${
+            depLoad.a[1].map(({ s, e }, i) => {
+              const q = depLoad.S[s] === '"' || depLoad.S[s] === "'";
+              return `e$_${i}=m${q ? `[` : '.'}${depLoad.S.slice(s, e)}${q ? `]` : ''}`;
+            }).join(',')
+          }}${
+            depLoad.a[1].length ? `let ${depLoad.a[1].map((_, i) => `e$_${i}`).join(',')};` : ''
+          }export {${
+            depLoad.a[1].map(({ s, e }, i) => `e$_${i} as ${depLoad.S.slice(s, e)}`).join(',')
+          }}\n//# sourceURL=${depLoad.r}?cycle`);
           }
-          lastIndex = statementEnd;
-        }
-        // import.meta
-        else if (dynamicImportIndex === -2) {
-          load.m = { url: load.r, resolve: metaResolve };
-          metaHook(load.m, load.u);
-          pushStringTo(start);
-          resolvedSource += `importShim._r[${urlJsString(load.u)}].m`;
-          lastIndex = statementEnd;
         }
-        // dynamic import
-        else {
-          pushStringTo(statementStart + 6);
-          resolvedSource += `Shim(`;
-          dynamicImportEndStack.push(statementEnd - 1);
-          lastIndex = start;
+
+        pushStringTo(start - 1);
+        resolvedSource += `/*${source.slice(start - 1, statementEnd)}*/${urlJsString(blobUrl)}`;
+
+        // circular shell execution
+        if (!cycleShell && depLoad.s) {
+          resolvedSource += `;import*as m$_${depIndex} from'${depLoad.b}';import{u$_ as u$_${depIndex}}from'${depLoad.s}';u$_${depIndex}(m$_${depIndex})`;
+          depLoad.s = undefined;
         }
+        lastIndex = statementEnd;
       }
+      // import.meta
+      else if (dynamicImportIndex === -2) {
+        load.m = { url: load.r, resolve: metaResolve };
+        metaHook(load.m, load.u);
+        pushStringTo(start);
+        resolvedSource += `importShim._r[${urlJsString(load.u)}].m`;
+        lastIndex = statementEnd;
+      }
+      // dynamic import
+      else {
+        pushStringTo(statementStart + 6);
+        resolvedSource += `Shim(`;
+        dynamicImportEndStack.push(statementEnd - 1);
+        lastIndex = start;
+      }
+    }
+
+    // support progressive cycle binding updates (try statement avoids tdz errors)
+    if (load.s)
+      resolvedSource += `\n;import{u$_}from'${load.s}';try{u$_({${exports.filter(e => e.ln).map(({ s, e, ln }) => `${source.slice(s, e)}:${ln}`).join(',')}})}catch(_){};\n`;
+
+    function pushSourceURL (commentPrefix, commentStart) {
+      const urlStart = commentStart + commentPrefix.length;
+      const commentEnd = source.indexOf('\n', urlStart);
+      const urlEnd = commentEnd !== -1 ? commentEnd : source.length;
+      pushStringTo(urlStart);
+      resolvedSource += new URL(source.slice(urlStart, urlEnd), load.r).href;
+      lastIndex = urlEnd;
+    }
+
+    let sourceURLCommentStart = source.lastIndexOf(sourceURLCommentPrefix);
+    let sourceMapURLCommentStart = source.lastIndexOf(sourceMapURLCommentPrefix);
 
-      // support progressive cycle binding updates (try statement avoids tdz errors)
-      if (load.s)
-        resolvedSource += `\n;import{u$_}from'${load.s}';try{u$_({${exports.filter(e => e.ln).map(({ s, e, ln }) => `${source.slice(s, e)}:${ln}`).join(',')}})}catch(_){};\n`;
+    // ignore sourceMap comments before already spliced code
+    if (sourceURLCommentStart < lastIndex) sourceURLCommentStart = -1;
+    if (sourceMapURLCommentStart < lastIndex) sourceMapURLCommentStart = -1;
 
-      pushStringTo(source.length);
+    // sourceURL first / only
+    if (sourceURLCommentStart !== -1 && (sourceMapURLCommentStart === -1 || sourceMapURLCommentStart > sourceURLCommentStart)) {
+      pushSourceURL(sourceURLCommentPrefix, sourceURLCommentStart);
     }
+    // sourceMappingURL
+    if (sourceMapURLCommentStart !== -1) {
+      pushSourceURL(sourceMapURLCommentPrefix, sourceMapURLCommentStart);
+      // sourceURL last
+      if (sourceURLCommentStart !== -1 && (sourceURLCommentStart > sourceMapURLCommentStart))
+        pushSourceURL(sourceURLCommentPrefix, sourceURLCommentStart);
+    }
+
+    pushStringTo(source.length);
 
-    let hasSourceURL = false;
-    resolvedSource = resolvedSource.replace(sourceMapURLRegEx, (match, isMapping, url) => (hasSourceURL = !isMapping, match.replace(url, () => new URL(url, load.r))));
-    if (!hasSourceURL)
-      resolvedSource += '\n//# sourceURL=' + load.r;
+    if (sourceURLCommentStart === -1)
+      resolvedSource += sourceURLCommentPrefix + load.r;
 
     load.b = lastLoad = createBlob(resolvedSource);
     load.S = undefined;
   }
 
-  // ; and // trailer support added for Ruby on Rails 7 source maps compatibility
-  // https://github.com/guybedford/es-module-shims/issues/228
-  const sourceMapURLRegEx = /\n\/\/# source(Mapping)?URL=([^\n]+)\s*((;|\/\/[^#][^\n]*)\s*)*$/;
+  const sourceURLCommentPrefix = '\n//# sourceURL=';
+  const sourceMapURLCommentPrefix = '\n//# sourceMappingURL=';
 
   const jsContentType = /^(text|application)\/(x-)?javascript(;|$)/;
   const jsonContentType = /^(text|application)\/json(;|$)/;