Common Type Fixes (ethereumjs#3307)

* Common: Improve typing for getHardforkBy()

* Common: Fixes type issue in paramByHardfork()

packages/common/src/common.ts

@@ -328,11 +328,9 @@ export class Common {
    * @returns The name of the HF
    */
   getHardforkBy(opts: HardforkByOpts): string {
-    let { blockNumber, timestamp, td } = opts
-
-    blockNumber = toType(blockNumber, TypeOutput.BigInt)
-    td = toType(td, TypeOutput.BigInt)
-    timestamp = toType(timestamp, TypeOutput.BigInt)
+    const blockNumber: bigint | undefined = toType(opts.blockNumber, TypeOutput.BigInt)
+    const td: bigint | undefined = toType(opts.td, TypeOutput.BigInt)
+    const timestamp: bigint | undefined = toType(opts.timestamp, TypeOutput.BigInt)
 
     // Filter out hardforks with no block number, no ttd or no timestamp (i.e. unapplied hardforks)
     const hfs = this.hardforks().filter(
@@ -353,10 +351,8 @@ export class Common {
     // discovering/checking number hardforks.
     let hfIndex = hfs.findIndex(
       (hf) =>
-        (blockNumber !== undefined &&
-          hf.block !== null &&
-          BigInt(hf.block) > (blockNumber as bigint)) ||
-        (timestamp !== undefined && hf.timestamp !== undefined && hf.timestamp > timestamp)
+        (blockNumber !== undefined && hf.block !== null && BigInt(hf.block) > blockNumber) ||
+        (timestamp !== undefined && hf.timestamp !== undefined && BigInt(hf.timestamp) > timestamp)
     )
 
     if (hfIndex === -1) {
@@ -601,7 +597,7 @@ export class Common {
    * @returns The value requested or `BigInt(0)` if not found
    */
   paramByHardfork(topic: string, name: string, hardfork: string | Hardfork): bigint {
-    let value = null
+    let value: bigint | null = null
     for (const hfChanges of this.HARDFORK_CHANGES) {
       // EIP-referencing HF config (e.g. for berlin)
       if ('eips' in hfChanges[1]) {