fix: throw when getExplorerLink has no block explorer URL available

Author: gabitoesmiapodo

src/utils/getExplorerLink.test.ts

@@ -0,0 +1,51 @@
+import type { Chain } from 'viem'
+import { describe, expect, it } from 'vitest'
+import { getExplorerLink } from './getExplorerLink'
+
+const chain: Chain = {
+  id: 1,
+  name: 'Mock Chain',
+  nativeCurrency: { name: 'Ether', symbol: 'ETH', decimals: 18 },
+  rpcUrls: { default: { http: ['https://mock.rpc.url'] } },
+  blockExplorers: {
+    default: { name: 'MockExplorer', url: 'https://mock.explorer.url' },
+  },
+} as Chain
+
+const address = '0x71C7656EC7ab88b098defB751B7401B5f6d8976F' as const
+const txHash = '0xd85ef8c70dc31a4f8d5bf0331e1eac886935905f15d32e71b348df745cd38e19' as const
+
+describe('getExplorerLink', () => {
+  it('returns address URL using chain block explorer', () => {
+    expect(getExplorerLink({ chain, hashOrAddress: address })).toBe(
+      `https://mock.explorer.url/address/${address}`,
+    )
+  })
+
+  it('returns tx URL using chain block explorer for a hash', () => {
+    expect(getExplorerLink({ chain, hashOrAddress: txHash })).toBe(
+      `https://mock.explorer.url/tx/${txHash}`,
+    )
+  })
+
+  it('uses custom explorerUrl when provided', () => {
+    const explorerUrl = 'https://custom.explorer.io'
+    expect(getExplorerLink({ chain, hashOrAddress: address, explorerUrl })).toBe(
+      `${explorerUrl}/address/${address}`,
+    )
+  })
+
+  it('throws when chain has no block explorer and no explorerUrl is provided', () => {
+    const chainWithoutExplorer: Chain = { ...chain, blockExplorers: undefined }
+    expect(() => getExplorerLink({ chain: chainWithoutExplorer, hashOrAddress: address })).toThrow(
+      'No block explorer URL available for this chain',
+    )
+  })
+
+  it('throws for an invalid hash or address', () => {
+    expect(() =>
+      // biome-ignore lint/suspicious/noExplicitAny: intentionally testing invalid input
+      getExplorerLink({ chain, hashOrAddress: 'not-valid' as any }),
+    ).toThrow('Invalid hash or address')
+  })
+})

src/utils/getExplorerLink.ts

@@ -19,6 +19,7 @@ export type GetExplorerUrlParams = {
  * @param {string} [params.explorerUrl] - Optional custom explorer URL to override the chain's default explorer
  *
  * @throws {Error} Throws an error if the provided hash or address is invalid
+ * @throws {Error} Throws an error if no explorer URL is available (neither `explorerUrl` nor `chain.blockExplorers`)
  *
  * @returns {string} The complete explorer URL for the given hash or address
  *
@@ -43,15 +44,17 @@ export type GetExplorerUrlParams = {
  * ```
  */
 export const getExplorerLink = ({ chain, explorerUrl, hashOrAddress }: GetExplorerUrlParams) => {
+  const baseUrl = explorerUrl ?? chain.blockExplorers?.default.url
+
+  if (!baseUrl) {
+    throw new Error('No block explorer URL available for this chain')
+  }
+
   if (isAddress(hashOrAddress)) {
-    return explorerUrl
-      ? `${explorerUrl}/address/${hashOrAddress}`
-      : `${chain.blockExplorers?.default.url}/address/${hashOrAddress}`
+    return `${baseUrl}/address/${hashOrAddress}`
   }
   if (isHash(hashOrAddress)) {
-    return explorerUrl
-      ? `${explorerUrl}/tx/${hashOrAddress}`
-      : `${chain.blockExplorers?.default.url}/tx/${hashOrAddress}`
+    return `${baseUrl}/tx/${hashOrAddress}`
   }
 
   throw new Error('Invalid hash or address')