perf: optimize binary search (#3)

inottn · May 12, 2024 · e0221f5 · e0221f5
1 parent 4725cff
commit e0221f5
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Showing 2 changed files with 7 additions and 7 deletions.
diff --git a/src/index.ts b/src/index.ts
@@ -224,15 +224,17 @@ export class MiniPoster {
   getAllLines(data: TextConfig) {
     const { context } = this;
     const { width, content, lineClamp = Infinity } = data;
+    const contentLength = content.length;
     const lines = [];
     let index = 0;
 
-    while (index < content.length && lines.length < lineClamp) {
+    while (index < contentLength && lines.length < lineClamp) {
       const prevIndex = index;
 
       index =
         binarySearch(
-          content,
+          index,
+          contentLength,
           (end) =>
             context.measureText(content.slice(index, end + 1)).width > width!,
         ) + 1;
@@ -241,7 +243,7 @@ export class MiniPoster {
         index = prevIndex + 1;
       }
 
-      if (lineClamp === lines.length + 1 && index < content.length) {
+      if (lineClamp === lines.length + 1 && index < contentLength) {
         lines.push(content.slice(prevIndex, index - 1) + '...');
       } else {
         lines.push(content.slice(prevIndex, index));

diff --git a/src/utils.ts b/src/utils.ts
@@ -9,12 +9,10 @@ import type {
 type BinarySearchValidate = (index: number) => boolean;
 
 export const binarySearch = function (
-  value: string,
+  left: number,
+  right: number,
   validate: BinarySearchValidate,
 ) {
-  let left = 0;
-  let right = value.length;
-
   while (left < right) {
     const mid = left + ((right - left) >> 1);