fix: guard against empty-string crash in fieldNorm

`value.match(SPACE)` returns `null` when there are no word tokens
(e.g. empty string). The old code used `!` (non-null assertion), which
throws. Changed to `?.length || 1` — treats zero-token input as 1
token, producing a norm of 1.0. This can happen if a custom `getFn`
returns `""` that slips past the `isBlank` guard.

Author: krisk

dist/fuse.basic.cjs

@@ -223,7 +223,7 @@ function norm(weight = 1, mantissa = 3) {
   const m = Math.pow(10, mantissa);
   return {
     get(value) {
-      const numTokens = value.match(SPACE).length;
+      const numTokens = value.match(SPACE)?.length || 1;
       if (cache.has(numTokens)) {
         return cache.get(numTokens);
       }

dist/fuse.basic.min.cjs

@@ -221,7 +221,7 @@ function norm(weight = 1, mantissa = 3) {
   const m = Math.pow(10, mantissa);
   return {
     get(value) {
-      const numTokens = value.match(SPACE).length;
+      const numTokens = value.match(SPACE)?.length || 1;
       if (cache.has(numTokens)) {
         return cache.get(numTokens);
       }

dist/fuse.basic.min.mjs

@@ -220,7 +220,7 @@ function norm(weight = 1, mantissa = 3) {
   const m = Math.pow(10, mantissa);
   return {
     get(value) {
-      const numTokens = value.match(SPACE).length;
+      const numTokens = value.match(SPACE)?.length || 1;
       if (cache.has(numTokens)) {
         return cache.get(numTokens);
       }

dist/fuse.basic.mjs

@@ -218,7 +218,7 @@ function norm(weight = 1, mantissa = 3) {
   const m = Math.pow(10, mantissa);
   return {
     get(value) {
-      const numTokens = value.match(SPACE).length;
+      const numTokens = value.match(SPACE)?.length || 1;
       if (cache.has(numTokens)) {
         return cache.get(numTokens);
       }

dist/fuse.cjs

@@ -218,7 +218,7 @@ function norm(weight = 1, mantissa = 3) {
   const m = Math.pow(10, mantissa);
   return {
     get(value) {
-      const numTokens = value.match(SPACE).length;
+      const numTokens = value.match(SPACE)?.length || 1;
       if (cache.has(numTokens)) {
         return cache.get(numTokens);
       }