url: replace "magic" numbers by constants

PR-URL: #19300
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>

Author: daynin

lib/internal/constants.js

@@ -39,6 +39,8 @@ module.exports = {
   CHAR_CIRCUMFLEX_ACCENT: 94, /* ^ */
   CHAR_GRAVE_ACCENT: 96, /* ` */
   CHAR_AT: 64, /* @ */
+  CHAR_AMPERSAND: 38, /* & */
+  CHAR_EQUAL: 61, /* = */
 
   // Digits
   CHAR_0: 48, /* 0 */

lib/internal/url.js

@@ -19,6 +19,14 @@ const {
   ERR_INVALID_URL_SCHEME,
   ERR_MISSING_ARGS
 } = require('internal/errors').codes;
+const {
+  CHAR_PERCENT,
+  CHAR_PLUS,
+  CHAR_AMPERSAND,
+  CHAR_EQUAL,
+  CHAR_LOWERCASE_A,
+  CHAR_LOWERCASE_Z,
+} = require('internal/constants');
 const querystring = require('querystring');
 
 const { platform } = process;
@@ -712,7 +720,7 @@ function parseParams(qs) {
     const code = qs.charCodeAt(i);
 
     // Try matching key/value pair separator
-    if (code === 38/* & */) {
+    if (code === CHAR_AMPERSAND) {
       if (pairStart === i) {
         // We saw an empty substring between pair separators
         lastPos = pairStart = i + 1;
@@ -738,7 +746,7 @@ function parseParams(qs) {
     }
 
     // Try matching key/value separator (e.g. '=') if we haven't already
-    if (!seenSep && code === 61/* = */) {
+    if (!seenSep && code === CHAR_EQUAL) {
       // Key/value separator match!
       if (lastPos < i)
         buf += qs.slice(lastPos, i);
@@ -755,15 +763,15 @@ function parseParams(qs) {
     }
 
     // Handle + and percent decoding.
-    if (code === 43/* + */) {
+    if (code === CHAR_PLUS) {
       if (lastPos < i)
         buf += qs.slice(lastPos, i);
       buf += ' ';
       lastPos = i + 1;
     } else if (!encoded) {
       // Try to match an (valid) encoded byte (once) to minimize unnecessary
       // calls to string decoding functions
-      if (code === 37/* % */) {
+      if (code === CHAR_PERCENT) {
         encodeCheck = 1;
       } else if (encodeCheck > 0) {
         // eslint-disable-next-line no-extra-boolean-cast
@@ -1357,7 +1365,7 @@ function getPathFromURLWin32(url) {
     // Otherwise, it's a local path that requires a drive letter
     var letter = pathname.codePointAt(1) | 0x20;
     var sep = pathname[2];
-    if (letter < 97 || letter > 122 ||   // a..z A..Z
+    if (letter < CHAR_LOWERCASE_A || letter > CHAR_LOWERCASE_Z ||   // a..z A..Z
         (sep !== ':')) {
       throw new ERR_INVALID_FILE_URL_PATH('must be absolute');
     }