Add GitHub Actions CI

Author: MikeMcl

.github/workflows/ci.yml

@@ -0,0 +1,28 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    name: Test on Node.js ${{ matrix.node-version }}
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: ['8', '18', '20', '22']
+      fail-fast: false
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Run Tests
+        run: npm test

big.mjs

@@ -965,6 +965,7 @@ P.toJSON = P.toString = function () {
     Big = x.constructor;
   return stringify(x, x.e <= Big.NE || x.e >= Big.PE, !!x.c[0]);
 };
+
 if (typeof Symbol !== "undefined") {
   P[Symbol.for('nodejs.util.inspect.custom')] = P.toJSON;
 }