From 493e7bf774e274be33257afb2b742c022e9f5664 Mon Sep 17 00:00:00 2001
From: LoneRifle <LoneRifle@users.noreply.github.com>
Date: Sat, 15 Jul 2023 11:16:40 +0800
Subject: [PATCH 1/2] Limit imports from `./types` to type where applicable

---
 src/c14n-canonicalization.ts      | 2 +-
 src/enveloped-signature.ts        | 2 +-
 src/exclusive-canonicalization.ts | 2 +-
 src/hash-algorithms.ts            | 2 +-
 src/signature-algorithms.ts       | 2 +-
 src/signed-xml.ts                 | 2 +-
 src/utils.ts                      | 2 +-
 7 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/c14n-canonicalization.ts b/src/c14n-canonicalization.ts
index 7625217a..03406145 100644
--- a/src/c14n-canonicalization.ts
+++ b/src/c14n-canonicalization.ts
@@ -1,4 +1,4 @@
-import {
+import type {
   CanonicalizationOrTransformationAlgorithm,
   CanonicalizationOrTransformationAlgorithmProcessOptions,
   NamespacePrefix,
diff --git a/src/enveloped-signature.ts b/src/enveloped-signature.ts
index ab898bd4..80a0a553 100644
--- a/src/enveloped-signature.ts
+++ b/src/enveloped-signature.ts
@@ -1,6 +1,6 @@
 import * as xpath from "xpath";
 
-import {
+import type {
   CanonicalizationOrTransformationAlgorithm,
   CanonicalizationOrTransformationAlgorithmProcessOptions,
   CanonicalizationOrTransformAlgorithmType,
diff --git a/src/exclusive-canonicalization.ts b/src/exclusive-canonicalization.ts
index 06eea343..4f76c83a 100644
--- a/src/exclusive-canonicalization.ts
+++ b/src/exclusive-canonicalization.ts
@@ -1,4 +1,4 @@
-import {
+import type {
   CanonicalizationOrTransformationAlgorithm,
   CanonicalizationOrTransformationAlgorithmProcessOptions,
   NamespacePrefix,
diff --git a/src/hash-algorithms.ts b/src/hash-algorithms.ts
index 56f6c896..eeeb8b27 100644
--- a/src/hash-algorithms.ts
+++ b/src/hash-algorithms.ts
@@ -1,5 +1,5 @@
 import * as crypto from "crypto";
-import { HashAlgorithm } from "./types";
+import type { HashAlgorithm } from "./types";
 
 export class Sha1 implements HashAlgorithm {
   getHash = function (xml) {
diff --git a/src/signature-algorithms.ts b/src/signature-algorithms.ts
index 71a23ed8..46abe0eb 100644
--- a/src/signature-algorithms.ts
+++ b/src/signature-algorithms.ts
@@ -1,5 +1,5 @@
 import * as crypto from "crypto";
-import { SignatureAlgorithm, createOptionalCallbackFunction } from "./types";
+import { type SignatureAlgorithm, createOptionalCallbackFunction } from "./types";
 
 export class RsaSha1 implements SignatureAlgorithm {
   getSignature = createOptionalCallbackFunction(
diff --git a/src/signed-xml.ts b/src/signed-xml.ts
index b2c0ca0f..072201ff 100644
--- a/src/signed-xml.ts
+++ b/src/signed-xml.ts
@@ -1,4 +1,4 @@
-import {
+import type {
   CanonicalizationAlgorithmType,
   CanonicalizationOrTransformationAlgorithm,
   ComputeSignatureOptions,
diff --git a/src/utils.ts b/src/utils.ts
index e58a95d3..c66a4ac1 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,5 +1,5 @@
 import * as xpath from "xpath";
-import { NamespacePrefix } from "./types";
+import type { NamespacePrefix } from "./types";
 
 export function isArrayHasLength(array: unknown): array is unknown[] {
   return Array.isArray(array) && array.length > 0;

From c9ba5b614df5ea766f9afc2b6b9ab65c5af457db Mon Sep 17 00:00:00 2001
From: LoneRifle <LoneRifle@users.noreply.github.com>
Date: Sat, 15 Jul 2023 11:21:47 +0800
Subject: [PATCH 2/2] findAncestorNs: replace type coercion with type guard

---
 src/utils.ts | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/utils.ts b/src/utils.ts
index c66a4ac1..2bb860a8 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -207,6 +207,10 @@ function findNSPrefix(subset) {
   return subset.prefix || "";
 }
 
+function isElementSubset(docSubset: Node[]): docSubset is Element[] {
+  return docSubset.every((node) => xpath.isElement(node))
+}
+
 /**
  * Extract ancestor namespaces in order to import it to root of document subset
  * which is being canonicalized for non-exclusive c14n.
@@ -222,20 +226,17 @@ export function findAncestorNs(
   namespaceResolver?: XPathNSResolver
 ) {
   const docSubset = xpath.selectWithResolver(docSubsetXpath, doc, namespaceResolver);
-  let elementSubset: Element[] = [];
 
   if (!isArrayHasLength(docSubset)) {
     return [];
   }
 
-  if (!docSubset.every((node) => xpath.isElement(node))) {
+  if (!isElementSubset(docSubset)) {
     throw new Error("Document subset must be list of elements");
-  } else {
-    elementSubset = docSubset as Element[];
   }
 
   // Remove duplicate on ancestor namespace
-  const ancestorNs = collectAncestorNamespaces(elementSubset[0]);
+  const ancestorNs = collectAncestorNamespaces(docSubset[0]);
   const ancestorNsWithoutDuplicate: NamespacePrefix[] = [];
   for (let i = 0; i < ancestorNs.length; i++) {
     let notOnTheList = true;