Adding upstream version 48.2.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

js/misc/errorUtils.js

@@ -0,0 +1,66 @@
+// Common code for displaying errors to the user in various dialogs
+
+function formatSyntaxErrorLocation(error) {
+    const {fileName = '<unknown>', lineNumber = 0, columnNumber = 0} = error;
+    return ` @ ${fileName}:${lineNumber}:${columnNumber}`;
+}
+
+function formatExceptionStack(error) {
+    const {stack} = error;
+    if (!stack)
+        return '\n\n(No stack trace)';
+
+    const indentedStack = stack.split('\n').map(line => `  ${line}`).join('\n');
+    return `\n\nStack trace:\n${indentedStack}`;
+}
+
+function formatExceptionWithCause(error, seenCauses, showStack) {
+    let fmt = showStack ? formatExceptionStack(error) : '';
+
+    const {cause} = error;
+    if (!cause)
+        return fmt;
+
+    fmt += `\nCaused by: ${cause}`;
+
+    if (cause !== null && typeof cause === 'object') {
+        if (seenCauses.has(cause))
+            return fmt;  // avoid recursion
+        seenCauses.add(cause);
+
+        fmt += formatExceptionWithCause(cause, seenCauses);
+    }
+
+    return fmt;
+}
+
+/**
+ * Formats a thrown exception into a string, including the stack, taking the
+ * location where a SyntaxError was thrown into account.
+ *
+ * @param {Error} error The error to format
+ * @param {object} options Formatting options
+ * @param {boolean} options.showStack Whether to show the stack trace (default
+ *   true)
+ * @returns {string} The formatted string
+ */
+export function formatError(error, {showStack = true} = {}) {
+    try {
+        let fmt = `${error}`;
+        if (error === null || typeof error !== 'object')
+            return fmt;
+
+        if (error instanceof SyntaxError) {
+            fmt += formatSyntaxErrorLocation(error);
+            if (showStack)
+                fmt += formatExceptionStack(error);
+            return fmt;
+        }
+
+        const seenCauses = new Set([error]);
+        fmt += formatExceptionWithCause(error, seenCauses, showStack);
+        return fmt;
+    } catch (e) {
+        return `(could not display error: ${e})`;
+    }
+}