util: support BigInt in util.format

`util.format` and `console.log` now support BigInt via the existing
format specifiers `%i` and `%d`.

PR-URL: https://github.com/nodejs/node/pull/22097
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 14 insertions, 2 deletions

diff --git a/lib/util.js b/lib/util.js
index 27affda109..2e42beb58b 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -102,7 +102,13 @@ function formatWithOptions(inspectOptions, f) {
             tempStr = tryStringify(arguments[a++]);
             break;
           case 100: // 'd'
-            tempStr = `${Number(arguments[a++])}`;
+            const tempNum = arguments[a++];
+            // eslint-disable-next-line valid-typeof
+            if (typeof tempNum === 'bigint') {
+              tempStr = `${tempNum}n`;
+            } else {
+              tempStr = `${Number(tempNum)}`;
+            }
             break;
           case 79: // 'O'
             tempStr = inspect(arguments[a++], inspectOptions);
@@ -117,7 +123,13 @@ function formatWithOptions(inspectOptions, f) {
             break;
           }
           case 105: // 'i'
-            tempStr = `${parseInt(arguments[a++])}`;
+            const tempInteger = arguments[a++];
+            // eslint-disable-next-line valid-typeof
+            if (typeof tempInteger === 'bigint') {
+              tempStr = `${tempInteger}n`;
+            } else {
+              tempStr = `${parseInt(tempInteger)}`;
+            }
             break;
           case 102: // 'f'
             tempStr = `${parseFloat(arguments[a++])}`;