function utf8ToBytes()

in web-ui/src/js/axios.js [2110:2188]
60 lines of code
22 McCabe index (conditional complexity)

	function utf8ToBytes (string, units) {
	  units = units || Infinity
	  var codePoint
	  var length = string.length
	  var leadSurrogate = null
	  var bytes = []
	
	  for (var i = 0; i < length; ++i) {
	    codePoint = string.charCodeAt(i)
	
	    // is surrogate component
	    if (codePoint > 0xD7FF && codePoint < 0xE000) {
	      // last char was a lead
	      if (!leadSurrogate) {
	        // no lead yet
	        if (codePoint > 0xDBFF) {
	          // unexpected trail
	          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
	          continue
	        } else if (i + 1 === length) {
	          // unpaired lead
	          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
	          continue
	        }
	
	        // valid lead
	        leadSurrogate = codePoint
	
	        continue
	      }
	
	      // 2 leads in a row
	      if (codePoint < 0xDC00) {
	        if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
	        leadSurrogate = codePoint
	        continue
	      }
	
	      // valid surrogate pair
	      codePoint = (leadSurrogate - 0xD800 << 10 | codePoint - 0xDC00) + 0x10000
	    } else if (leadSurrogate) {
	      // valid bmp char, but last char was a lead
	      if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
	    }
	
	    leadSurrogate = null
	
	    // encode utf8
	    if (codePoint < 0x80) {
	      if ((units -= 1) < 0) break
	      bytes.push(codePoint)
	    } else if (codePoint < 0x800) {
	      if ((units -= 2) < 0) break
	      bytes.push(
	        codePoint >> 0x6 | 0xC0,
	        codePoint & 0x3F | 0x80
	      )
	    } else if (codePoint < 0x10000) {
	      if ((units -= 3) < 0) break
	      bytes.push(
	        codePoint >> 0xC | 0xE0,
	        codePoint >> 0x6 & 0x3F | 0x80,
	        codePoint & 0x3F | 0x80
	      )
	    } else if (codePoint < 0x110000) {
	      if ((units -= 4) < 0) break
	      bytes.push(
	        codePoint >> 0x12 | 0xF0,
	        codePoint >> 0xC & 0x3F | 0x80,
	        codePoint >> 0x6 & 0x3F | 0x80,
	        codePoint & 0x3F | 0x80
	      )
	    } else {
	      throw new Error('Invalid code point')
	    }
	  }
	
	  return bytes
	}