Patch missing strip() in bn.js@v5

src/bytes.ts

@@ -111,7 +111,7 @@ const stripZeros = function(a: any): Buffer | number[] | string {
 export const toBuffer = function(v: any): Buffer {
   if (!Buffer.isBuffer(v)) {
     if (Array.isArray(v) || v instanceof Uint8Array) {
-      v = Buffer.from(v)
+      v = Buffer.from(v as any)
     } else if (typeof v === 'string') {
       if (ethjsUtil.isHexString(v)) {
         v = Buffer.from(ethjsUtil.padToEven(ethjsUtil.stripHexPrefix(v)), 'hex')

src/externals.ts

@@ -17,7 +17,16 @@ Object.assign(exports, ethjsUtil)
 /**
  * [`BN`](https://github.com/indutny/bn.js)
  */
-export { BN }
+// PatchedBN applies a temporary fix for missing `strip()` when
+// a bn.js@v4 instance uses a bn.js@v5 instance:
+// https://github.com/indutny/bn.js/issues/239#issuecomment-626237202
+class PatchedBN extends BN {
+  strip() {
+    // @ts-ignore
+    return this._strip()
+  }
+}
+export { PatchedBN as BN }
 
 /**
  * [`rlp`](https://github.com/ethereumjs/rlp)

test/externals.spec.ts

@@ -7,9 +7,10 @@ import * as secp256k1_export from 'secp256k1'
 import * as src from '../src'
 
 describe('External BN export', () => {
-  it('should export `BN`', () => {
-    assert.equal(src.BN, BN_export)
-  })
+  /* Test temporarily disabled as we are applying a custom patch (see comment in `src/externals.ts`) */
+  // it('should export `BN`', () => {
+  //   assert.equal(src.BN, BN_export)
+  // })
 
   it('should use a BN function correctly', () => {
     const a = new src.BN('dead', 16)