assert: make skipping indicator blue

If lines gets skipped, they are marked with three dots. This makes
sure they are better visualized to distinguish them from everything
else.
PR-URL: #20315
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>

Author: BridgeAR

lib/internal/errors.js

@@ -15,6 +15,7 @@ const kInfo = Symbol('info');
 constmessages=newMap();
 constcodes={};
 
+letblue='';
 letgreen='';
 letred='';
 letwhite='';
@@ -259,7 +260,7 @@ function createErrDiff(actual, expected, operator) {
 constexpectedLines=inspectValue(expected);
 constmsg=READABLE_OPERATOR[operator]+
 `:\n${green}+ expected${white}${red}- actual${white}`;
-constskippedMsg=' ... Lines skipped';
+constskippedMsg=` ${blue}...${white} Lines skipped`;
 
 // Remove all ending lines that match (this optimizes the output for
 // readability by reducing the number of total changed lines).
@@ -280,7 +281,7 @@ function createErrDiff(actual, expected, operator) {
 b=expectedLines[expectedLines.length-1];
 }
 if(i>3){
-end=`\n...${end}`;
+end=`\n${blue}...${white}${end}`;
 skipped=true;
 }
 if(other!==''){
@@ -297,7 +298,7 @@ function createErrDiff(actual, expected, operator) {
 if(actualLines.length<i+1){
 if(cur>1&&i>2){
 if(cur>4){
-res+='\n...';
+res+=`\n${blue}...${white}`;
 skipped=true;
 }elseif(cur>3){
 res+=`\n ${expectedLines[i-2]}`;
@@ -313,7 +314,7 @@ function createErrDiff(actual, expected, operator) {
 }elseif(expectedLines.length<i+1){
 if(cur>1&&i>2){
 if(cur>4){
-res+='\n...';
+res+=`\n${blue}...${white}`;
 skipped=true;
 }elseif(cur>3){
 res+=`\n ${actualLines[i-2]}`;
@@ -329,7 +330,7 @@ function createErrDiff(actual, expected, operator) {
 }elseif(actualLines[i]!==expectedLines[i]){
 if(cur>1&&i>2){
 if(cur>4){
-res+='\n...';
+res+=`\n${blue}...${white}`;
 skipped=true;
 }elseif(cur>3){
 res+=`\n ${actualLines[i-2]}`;
@@ -354,7 +355,8 @@ function createErrDiff(actual, expected, operator) {
 }
 // Inspected object to big (Show ~20 rows max)
 if(printedLines>20&&i<maxLines-2){
-return`${msg}${skippedMsg}\n${res}\n...${other}\n...`;
+return`${msg}${skippedMsg}\n${res}\n${blue}...${white}${other}\n`+
+`${blue}...${white}`;
 }
 }
 
@@ -371,7 +373,7 @@ 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>30){
-actualLines[26]='...';
+actualLines[26]=`${blue}...${white}`;
 while(actualLines.length>27){
 actualLines.pop();
 }
@@ -402,10 +404,12 @@ class AssertionError extends Error {
 // Reset on each call to make sure we handle dynamically set environment
 // variables correct.
 if(process.stdout.getColorDepth()!==1){
+blue='\u001b[34m';
 green='\u001b[32m';
 white='\u001b[39m';
 red='\u001b[31m';
 }else{
+blue='';
 green='';
 white='';
 red='';
@@ -435,7 +439,7 @@ 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>30){
-res[26]='...';
+res[26]=`${blue}...${white}`;
 while(res.length>27){
 res.pop();
 }

test/pseudo-tty/test-assert-colors.js

@@ -5,13 +5,16 @@ const assert = require('assert').strict;
 try{
 // Activate colors even if the tty does not support colors.
 process.env.COLORTERM='1';
-assert.deepStrictEqual([1,2],[2,2]);
+assert.deepStrictEqual([1,2,2,2],[2,2,2,2]);
 }catch(err){
 constexpected='Input A expected to strictly deep-equal input B:\n'+
-'\u001b[32m+ expected\u001b[39m \u001b[31m- actual\u001b[39m\n\n'+
+'\u001b[32m+ expected\u001b[39m \u001b[31m- actual\u001b[39m'+
+' \u001b[34m...\u001b[39m Lines skipped\n\n'+
 ' [\n'+
 '\u001b[31m-\u001b[39m 1,\n'+
 '\u001b[32m+\u001b[39m 2,\n'+
+' 2,\n'+
+'\u001b[34m...\u001b[39m\n'+
 ' 2\n'+
 ' ]';
 assert.strictEqual(err.message,expected);