fix: break over-long words in one pass instead of re-queuing the tail

src/main.js

@@ -1,6 +1,5 @@
 'use strict'
 
-const breakword = require('breakword')
 const stripAnsi = require('strip-ansi')
 const wcwidth = require('wcwidth')
 
@@ -93,10 +92,31 @@ const wrap = (input, options) => {
 
       // too long for an empty line, must be broken across lines
       case lineLength < wordLength: {
-        const splitIndex = breakword(word, lineLength)
-        const splitWord = [...word]
-        words.unshift(splitWord.slice(0, splitIndex + 1).join(''))
-        words.splice(1, 0, splitWord.slice(splitIndex + 1).join(''))
+        // Break the whole word into line-sized chunks in a single pass.
+        // Re-queuing just the tail means the remainder is spread and measured
+        // again on every iteration, which is quadratic for a long word (a URL,
+        // token or base64 blob), so a ~125KB word takes tens of seconds.
+        const chunks = []
+        let chunk = ''
+        let chunkWidth = 0
+
+        for (const character of word) {
+          const characterWidth = wcwidth(character)
+          if (chunk !== '' && chunkWidth + characterWidth > lineLength) {
+            chunks.push(chunk)
+            chunk = ''
+            chunkWidth = 0
+          }
+          chunk += character
+          chunkWidth += characterWidth
+        }
+        if (chunk !== '') {
+          chunks.push(chunk)
+        }
+
+        // concat rather than unshift(...chunks): a long word can produce more
+        // chunks than the argument limit allows to be spread.
+        words = chunks.concat(words)
         break
       }