src: add encoding_type variable in WritePrivateKey

This commit adds a local variable named encoding_type which is set to
the value of the Maybe using ToChecked().

The motivation for this is the code for ToChecked() could be executed
multiple times depending on path taken at runtime. I also think this
improves readability, or at least it is as readable as before this
change.

PR-URL: #34181
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: David Carlier <devnexen@gmail.com>

src/node_crypto.cc

@@ -3151,7 +3151,8 @@ static MaybeLocal<Value> WritePrivateKey(
 
   bool err;
 
-  if (config.type_.ToChecked() == kKeyEncodingPKCS1) {
+  PKEncodingType encoding_type = config.type_.ToChecked();
+  if (encoding_type == kKeyEncodingPKCS1) {
     // PKCS#1 is only permitted for RSA keys.
     CHECK_EQ(EVP_PKEY_id(pkey), EVP_PKEY_RSA);
 
@@ -3171,7 +3172,7 @@ static MaybeLocal<Value> WritePrivateKey(
       CHECK_NULL(config.cipher_);
       err = i2d_RSAPrivateKey_bio(bio.get(), rsa.get()) != 1;
     }
-  } else if (config.type_.ToChecked() == kKeyEncodingPKCS8) {
+  } else if (encoding_type == kKeyEncodingPKCS8) {
     if (config.format_ == kKeyFormatPEM) {
       // Encode PKCS#8 as PEM.
       err = PEM_write_bio_PKCS8PrivateKey(
@@ -3191,7 +3192,7 @@ static MaybeLocal<Value> WritePrivateKey(
                 nullptr, nullptr) != 1;
     }
   } else {
-    CHECK_EQ(config.type_.ToChecked(), kKeyEncodingSEC1);
+    CHECK_EQ(encoding_type, kKeyEncodingSEC1);
 
     // SEC1 is only permitted for EC keys.
     CHECK_EQ(EVP_PKEY_id(pkey), EVP_PKEY_EC);