cli: add --watch

PR-URL: https://github.com/nodejs/node/pull/44366
Fixes: https://github.com/nodejs/node/issues/40429
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

lib/internal/assert/assertion_error.js

@@ -21,15 +21,12 @@ const { inspect } = require('internal/util/inspect');
 const {
   removeColors,
 } = require('internal/util');
+const colors = require('internal/util/colors');
 const {
   validateObject,
 } = require('internal/validators');
 const { isErrorStackTraceLimitWritable } = require('internal/errors');
 
-let blue = '';
-let green = '';
-let red = '';
-let white = '';
 
 const kReadableOperator = {
   deepStrictEqual: 'Expected values to be strictly deep-equal:',
@@ -169,7 +166,7 @@ function createErrDiff(actual, expected, operator) {
     // Only remove lines in case it makes sense to collapse those.
     // TODO: Accept env to always show the full error.
     if (actualLines.length > 50) {
-      actualLines[46] = `${blue}...${white}`;
+      actualLines[46] = `${colors.blue}...${colors.white}`;
       while (actualLines.length > 47) {
         ArrayPrototypePop(actualLines);
       }
@@ -182,7 +179,7 @@ function createErrDiff(actual, expected, operator) {
   // There were at least five identical lines at the end. Mark a couple of
   // skipped.
   if (i >= 5) {
-    end = `\n${blue}...${white}${end}`;
+    end = `\n${colors.blue}...${colors.white}${end}`;
     skipped = true;
   }
   if (other !== '') {
@@ -193,15 +190,15 @@ function createErrDiff(actual, expected, operator) {
   let printedLines = 0;
   let identical = 0;
   const msg = kReadableOperator[operator] +
-        `\n${green}+ actual${white} ${red}- expected${white}`;
-  const skippedMsg = ` ${blue}...${white} Lines skipped`;
+        `\n${colors.green}+ actual${colors.white} ${colors.red}- expected${colors.white}`;
+  const skippedMsg = ` ${colors.blue}...${colors.white} Lines skipped`;
 
   let lines = actualLines;
-  let plusMinus = `${green}+${white}`;
+  let plusMinus = `${colors.green}+${colors.white}`;
   let maxLength = expectedLines.length;
   if (actualLines.length < maxLines) {
     lines = expectedLines;
-    plusMinus = `${red}-${white}`;
+    plusMinus = `${colors.red}-${colors.white}`;
     maxLength = actualLines.length;
   }
 
@@ -216,7 +213,7 @@ function createErrDiff(actual, expected, operator) {
               res += `\n  ${lines[i - 3]}`;
               printedLines++;
             } else {
-              res += `\n${blue}...${white}`;
+              res += `\n${colors.blue}...${colors.white}`;
               skipped = true;
             }
           }
@@ -272,7 +269,7 @@ function createErrDiff(actual, expected, operator) {
                 res += `\n  ${actualLines[i - 3]}`;
                 printedLines++;
               } else {
-                res += `\n${blue}...${white}`;
+                res += `\n${colors.blue}...${colors.white}`;
                 skipped = true;
               }
             }
@@ -286,8 +283,8 @@ function createErrDiff(actual, expected, operator) {
         identical = 0;
         // Add the actual line to the result and cache the expected diverging
         // line so consecutive diverging lines show up as +++--- and not +-+-+-.
-        res += `\n${green}+${white} ${actualLine}`;
-        other += `\n${red}-${white} ${expectedLine}`;
+        res += `\n${colors.green}+${colors.white} ${actualLine}`;
+        other += `\n${colors.red}-${colors.white} ${expectedLine}`;
         printedLines += 2;
       // Lines are identical
       } else {
@@ -306,8 +303,8 @@ function createErrDiff(actual, expected, operator) {
     }
     // Inspected object to big (Show ~50 rows max)
     if (printedLines > 50 && i < maxLines - 2) {
-      return `${msg}${skippedMsg}\n${res}\n${blue}...${white}${other}\n` +
-             `${blue}...${white}`;
+      return `${msg}${skippedMsg}\n${res}\n${colors.blue}...${colors.white}${other}\n` +
+             `${colors.blue}...${colors.white}`;
     }
   }
 
@@ -347,21 +344,9 @@ class AssertionError extends Error {
     if (message != null) {
       super(String(message));
     } else {
-      if (process.stderr.isTTY) {
-        // Reset on each call to make sure we handle dynamically set environment
-        // variables correct.
-        if (process.stderr.hasColors()) {
-          blue = '\u001b[34m';
-          green = '\u001b[32m';
-          white = '\u001b[39m';
-          red = '\u001b[31m';
-        } else {
-          blue = '';
-          green = '';
-          white = '';
-          red = '';
-        }
-      }
+      // Reset colors on each call to make sure we handle dynamically set environment
+      // variables correct.
+      colors.refresh();
       // Prevent the error stack from being visible by duplicating the error
       // in a very close way to the original in case both sides are actually
       // instances of Error.
@@ -393,7 +378,7 @@ class AssertionError extends Error {
         // Only remove lines in case it makes sense to collapse those.
         // TODO: Accept env to always show the full error.
         if (res.length > 50) {
-          res[46] = `${blue}...${white}`;
+          res[46] = `${colors.blue}...${colors.white}`;
           while (res.length > 47) {
             ArrayPrototypePop(res);
           }