pretty-print long strings

js/console.ts

@@ -23,6 +23,8 @@ const DEFAULT_MAX_DEPTH = 4;
 // form.
 const OBJ_ABBREVIATE_SIZE = 5;
 
+const STR_ABBREVIATE_SIZE = 100;
+
 // Char codes
 const CHAR_PERCENT = 37; /* % */
 const CHAR_LOWERCASE_S = 115; /* s */
@@ -151,7 +153,11 @@ function stringifyWithQuotes(
 ): string {
   switch (typeof value) {
     case "string":
-      return `"${value}"`;
+      const trunc =
+        value.length > STR_ABBREVIATE_SIZE
+          ? value.slice(0, STR_ABBREVIATE_SIZE) + "..."
+          : value;
+      return JSON.stringify(trunc);
     default:
       return stringify(value, ctx, level, maxLevel);
   }

js/console_test.ts

@@ -31,6 +31,17 @@ test(function consoleTestStringifyComplexObjects() {
   assertEquals(stringify({ foo: "bar" }), `{ foo: "bar" }`);
 });
 
+test(function consoleTestStringifyLongStrings() {
+  const veryLongString = "a".repeat(200);
+  // If we stringify an object containing the long string, it gets abbreviated.
+  let actual = stringify({ veryLongString });
+  assert(actual.includes("..."));
+  assert(actual.length < 200);
+  // However if we stringify the string itself, we get it exactly.
+  actual = stringify(veryLongString);
+  assertEquals(actual, veryLongString);
+});
+
 test(function consoleTestStringifyCircular() {
   class Base {
     a = 1;