fix: update string hash algorithm (#542)

This fixes an cjs/esm import error with the farmhash-modern dependency.
The string hash algorithm is switched to use FNV-1a instead which has a
purejs implementation that works well on the server and in the browser.

Unit tests added as well to ensure future compatibility.

Author: stevenle

packages/root-cms/package.json

@@ -72,7 +72,7 @@
     "csv-parse": "5.5.2",
     "csv-stringify": "6.4.4",
     "dts-dom": "3.7.0",
-    "farmhash-modern": "1.1.0",
+    "fnv-plus": "1.3.1",
     "jsonwebtoken": "9.0.2",
     "kleur": "4.1.5",
     "sirv": "2.0.3",
@@ -102,6 +102,7 @@
     "@preact/compat": "17.1.2",
     "@tabler/icons-preact": "2.47.0",
     "@types/body-parser": "1.19.3",
+    "@types/fnv-plus": "1.3.2",
     "@types/gapi": "0.0.47",
     "@types/gapi.client.drive-v3": "0.0.4",
     "@types/gapi.client.sheets-v4": "0.0.4",

packages/root-cms/shared/strings.test.ts

@@ -0,0 +1,28 @@
+import {describe, it, expect} from 'vitest';
+import {hashStr} from './strings.js';
+
+describe('hashStr', () => {
+  it('generates consistent hash for input', () => {
+    const input = 'hello world';
+    // Run the hash twice to verify the output is consistent.
+    const hash1 = hashStr(input);
+    const hash2 = hashStr(input);
+    expect(hash1).toMatchInlineSnapshot('"a65e7023cd59e"');
+    expect(hash1).toEqual(hash2);
+  });
+
+  it('generates the same hash for strings with leading and trailing whitespace', () => {
+    const input1 = 'hello test';
+    const input2 = 'hello test ';
+    const input3 = '   hello test  ';
+    const input4 = 'hello test ';
+    const hash1 = hashStr(input1);
+    const hash2 = hashStr(input2);
+    const hash3 = hashStr(input3);
+    const hash4 = hashStr(input4);
+    expect(hash1).toMatchInlineSnapshot('"5a364db8899ed"');
+    expect(hash1).toEqual(hash2);
+    expect(hash1).toEqual(hash3);
+    expect(hash1).toEqual(hash4);
+  });
+});

packages/root-cms/shared/strings.ts

@@ -2,7 +2,7 @@
  * Shared utility functions for handling strings.
  */
 
-import * as farmhash from 'farmhash-modern';
+import fnv from 'fnv-plus';
 
 /**
  * Cleans a source string for use in translations. Performs the following:
@@ -24,12 +24,20 @@ function removeTrailingWhitespace(str: string) {
 /**
  * Returns a hash fingerprint for a string.
  *
- * Note that this hash function is meant to be fast and for collision avoidance
- * for use in a hash map, but is not intended for cryptographic purposes. For
- * these reasons farmhash is used here.
+ * Note that this hash function is meant to be fast and collision-free for use
+ * in a hash map, but is not intended for cryptographic purposes. For these
+ * reasons `FNV-1a` is used here.
  *
- * @see https://www.npmjs.com/package/farmhash-modern
+ * NOTE: farmhash-modern was previously tested here, but had issues with
+ * cjs/esm imports. A purejs implementation should be used here that can run on
+ * the server and in the browser.
+ *
+ * @see https://www.npmjs.com/package/fnv-plus
  */
 export function hashStr(str: string): string {
-  return String(farmhash.fingerprint32(normalizeStr(str)));
+  // Avoid hashing empty strings and invalid types.
+  if (!str || typeof str !== 'string') {
+    throw new Error('input string is invalid');
+  }
+  return fnv.fast1a52hex(normalizeStr(str));
 }