From 595903b4fe5aa793a8123057a2fa15d567660e5e Mon Sep 17 00:00:00 2001
From: lumburr <flyfish.zy@foxmail.com>
Date: Fri, 1 Apr 2022 21:58:52 +0800
Subject: [PATCH 1/3] fix: ESlint warning

---
 packages/less/.eslintrc.json                      | 3 +--
 packages/less/package.json                        | 4 +---
 packages/less/src/less-browser/utils.js           | 2 +-
 packages/less/src/less/environment/environment.js | 3 ++-
 packages/less/src/less/functions/default.js       | 3 ++-
 packages/less/src/less/functions/math-helper.js   | 3 ++-
 packages/less/src/less/parser/parser.js           | 2 +-
 packages/less/src/less/tree/node.js               | 8 +++++---
 packages/less/src/less/tree/quoted.js             | 3 ++-
 packages/less/src/less/tree/ruleset.js            | 2 +-
 packages/less/src/less/tree/selector.js           | 3 ++-
 packages/less/src/less/utils.js                   | 4 ++++
 12 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/packages/less/.eslintrc.json b/packages/less/.eslintrc.json
index 9713bafa8..da3174afb 100644
--- a/packages/less/.eslintrc.json
+++ b/packages/less/.eslintrc.json
@@ -1,10 +1,9 @@
 {
-    "parser": "@typescript-eslint/parser",
     "parserOptions": {
         "ecmaVersion": 2018,
         "sourceType": "module"
     },
-    "plugins": ["@typescript-eslint"],
+    "plugins": [],
     "env": {
         "browser": true,
         "node": true
diff --git a/packages/less/package.json b/packages/less/package.json
index 5976af2f0..55f85f30a 100644
--- a/packages/less/package.json
+++ b/packages/less/package.json
@@ -59,14 +59,12 @@
 		"@rollup/plugin-commonjs": "^17.0.0",
 		"@rollup/plugin-json": "^4.1.0",
 		"@rollup/plugin-node-resolve": "^11.0.0",
-		"@typescript-eslint/eslint-plugin": "^4.28.0",
-		"@typescript-eslint/parser": "^4.28.0",
 		"benny": "^3.6.12",
 		"bootstrap-less-port": "0.3.0",
 		"chai": "^4.2.0",
 		"cross-env": "^7.0.3",
 		"diff": "^3.2.0",
-		"eslint": "^7.29.0",
+		"eslint": "^8.10.0",
 		"fs-extra": "^8.1.0",
 		"git-rev": "^0.2.1",
 		"globby": "^10.0.1",
diff --git a/packages/less/src/less-browser/utils.js b/packages/less/src/less-browser/utils.js
index 42a1b442e..039f1d595 100644
--- a/packages/less/src/less-browser/utils.js
+++ b/packages/less/src/less-browser/utils.js
@@ -9,7 +9,7 @@ export function extractId(href) {
 }
 
 export function addDataAttr(options, tag) {
-	if(!tag) return; // in case of tag is null or undefined
+    if (!tag) {return;} // in case of tag is null or undefined
     for (const opt in tag.dataset) {
         if (tag.dataset.hasOwnProperty(opt)) {
             if (opt === 'env' || opt === 'dumpLineNumbers' || opt === 'rootpath' || opt === 'errorReporting') {
diff --git a/packages/less/src/less/environment/environment.js b/packages/less/src/less/environment/environment.js
index 39de0d315..ce85ad6a8 100644
--- a/packages/less/src/less/environment/environment.js
+++ b/packages/less/src/less/environment/environment.js
@@ -4,6 +4,7 @@
  */
 
 import logger from '../logger';
+import * as utils from '../utils';
 
 class Environment {
     constructor(externalEnvironment, fileManagers) {
@@ -30,7 +31,7 @@ class Environment {
         if (!filename) {
             logger.warn('getFileManager called with no filename.. Please report this issue. continuing.');
         }
-        if (currentDirectory == null) {
+        if (utils.isNullOrUndefined(currentDirectory)) {
             logger.warn('getFileManager called with null directory.. Please report this issue. continuing.');
         }
 
diff --git a/packages/less/src/less/functions/default.js b/packages/less/src/less/functions/default.js
index fc7fd63aa..61c14b9ac 100644
--- a/packages/less/src/less/functions/default.js
+++ b/packages/less/src/less/functions/default.js
@@ -1,4 +1,5 @@
 import Keyword from '../tree/keyword';
+import * as utils from '../utils';
 
 const defaultFunc = {
     eval: function () {
@@ -7,7 +8,7 @@ const defaultFunc = {
         if (e) {
             throw e;
         }
-        if (v != null) {
+        if (!utils.isNullOrUndefined(v)) {
             return v ? Keyword.True : Keyword.False;
         }
     },
diff --git a/packages/less/src/less/functions/math-helper.js b/packages/less/src/less/functions/math-helper.js
index ed6deaa75..e2bebce87 100644
--- a/packages/less/src/less/functions/math-helper.js
+++ b/packages/less/src/less/functions/math-helper.js
@@ -1,10 +1,11 @@
 import Dimension from '../tree/dimension';
+import * as utils from '../utils';
 
 const MathHelper = (fn, unit, n) => {
     if (!(n instanceof Dimension)) {
         throw { type: 'Argument', message: 'argument must be a number' };
     }
-    if (unit == null) {
+    if (utils.isNullOrUndefined(unit)) {
         unit = n.unit;
     } else {
         n = n.unify();
diff --git a/packages/less/src/less/parser/parser.js b/packages/less/src/less/parser/parser.js
index c7a65cb07..ea3383623 100644
--- a/packages/less/src/less/parser/parser.js
+++ b/packages/less/src/less/parser/parser.js
@@ -581,7 +581,7 @@ const Parser = function Parser(context, imports, fileInfo) {
 
                     expectChar(')');
 
-                    return new(tree.URL)((value.value != null || 
+                    return new(tree.URL)((!utils.isNullOrUndefined(value.value) || 
                         value instanceof tree.Variable || 
                         value instanceof tree.Property) ?
                         value : new(tree.Anonymous)(value, index), index, fileInfo);
diff --git a/packages/less/src/less/tree/node.js b/packages/less/src/less/tree/node.js
index b40e30da9..b2c74aff8 100644
--- a/packages/less/src/less/tree/node.js
+++ b/packages/less/src/less/tree/node.js
@@ -1,3 +1,5 @@
+import * as utils from '../utils';
+
 /**
  * The reason why Node is a class and other nodes simply do not extend
  * from Node (since we're transpiling) is due to this issue:
@@ -125,21 +127,21 @@ class Node {
 
     // Returns true if this node represents root of ast imported by reference
     blocksVisibility() {
-        if (this.visibilityBlocks == null) {
+        if (utils.isNullOrUndefined(this.visibilityBlocks)) {
             this.visibilityBlocks = 0;
         }
         return this.visibilityBlocks !== 0;
     }
 
     addVisibilityBlock() {
-        if (this.visibilityBlocks == null) {
+        if (utils.isNullOrUndefined(this.visibilityBlocks)) {
             this.visibilityBlocks = 0;
         }
         this.visibilityBlocks = this.visibilityBlocks + 1;
     }
 
     removeVisibilityBlock() {
-        if (this.visibilityBlocks == null) {
+        if (utils.isNullOrUndefined(this.visibilityBlocks)) {
             this.visibilityBlocks = 0;
         }
         this.visibilityBlocks = this.visibilityBlocks - 1;
diff --git a/packages/less/src/less/tree/quoted.js b/packages/less/src/less/tree/quoted.js
index d73c40ca6..20ea852a1 100644
--- a/packages/less/src/less/tree/quoted.js
+++ b/packages/less/src/less/tree/quoted.js
@@ -1,10 +1,11 @@
 import Node from './node';
 import Variable from './variable';
 import Property from './property';
+import * as utils from '../utils';
 
 
 const Quoted = function(str, content, escaped, index, currentFileInfo) {
-    this.escaped = (escaped == null) ? true : escaped;
+    this.escaped = utils.isNullOrUndefined(escaped) ? true : escaped;
     this.value = content || '';
     this.quote = str.charAt(0);
     this._index = index;
diff --git a/packages/less/src/less/tree/ruleset.js b/packages/less/src/less/tree/ruleset.js
index 22f68b75c..fbbe51be3 100644
--- a/packages/less/src/less/tree/ruleset.js
+++ b/packages/less/src/less/tree/ruleset.js
@@ -734,7 +734,7 @@ Ruleset.prototype = Object.assign(new Node(), {
                 // non parent reference elements just get added
                 if (el.value !== '&') {
                     const nestedSelector = findNestedSelector(el);
-                    if (nestedSelector != null) {
+                    if (!utils.isNullOrUndefined(nestedSelector)) {
                         // merge the current list of non parent selector elements
                         // on to the current list of selectors to add
                         mergeElementsOnToSelectors(currentElements, newSelectors);
diff --git a/packages/less/src/less/tree/selector.js b/packages/less/src/less/tree/selector.js
index a198a7740..d098cc2bc 100644
--- a/packages/less/src/less/tree/selector.js
+++ b/packages/less/src/less/tree/selector.js
@@ -1,6 +1,7 @@
 import Node from './node';
 import Element from './element';
 import LessError from '../less-error';
+import * as utils from '../utils';
 
 const Selector = function(elements, extendList, condition, index, currentFileInfo, visibilityInfo) {
     this.extendList = extendList;
@@ -33,7 +34,7 @@ Selector.prototype = Object.assign(new Node(), {
         elements = this.getElements(elements);
         const newSelector = new Selector(elements, extendList || this.extendList,
             null, this.getIndex(), this.fileInfo(), this.visibilityInfo());
-        newSelector.evaldCondition = (evaldCondition != null) ? evaldCondition : this.evaldCondition;
+        newSelector.evaldCondition = (!utils.isNullOrUndefined(evaldCondition)) ? evaldCondition : this.evaldCondition;
         newSelector.mediaEmpty = this.mediaEmpty;
         return newSelector;
     },
diff --git a/packages/less/src/less/utils.js b/packages/less/src/less/utils.js
index c0921b90d..b723ab2ac 100644
--- a/packages/less/src/less/utils.js
+++ b/packages/less/src/less/utils.js
@@ -119,4 +119,8 @@ export function flattenArray(arr, result = []) {
         }
     }
     return result;
+}
+
+export function isNullOrUndefined(val) {
+    return val === null || val === undefined
 }
\ No newline at end of file

From db88cc3877c84b6441c9642ba199481e21901cf7 Mon Sep 17 00:00:00 2001
From: lumburr <flyfish.zy@foxmail.com>
Date: Sat, 2 Apr 2022 10:46:51 +0800
Subject: [PATCH 2/3] fallback ts configuration

---
 packages/less/.eslintrc.json | 3 ++-
 packages/less/package.json   | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/less/.eslintrc.json b/packages/less/.eslintrc.json
index da3174afb..9713bafa8 100644
--- a/packages/less/.eslintrc.json
+++ b/packages/less/.eslintrc.json
@@ -1,9 +1,10 @@
 {
+    "parser": "@typescript-eslint/parser",
     "parserOptions": {
         "ecmaVersion": 2018,
         "sourceType": "module"
     },
-    "plugins": [],
+    "plugins": ["@typescript-eslint"],
     "env": {
         "browser": true,
         "node": true
diff --git a/packages/less/package.json b/packages/less/package.json
index 55f85f30a..1a09a13a9 100644
--- a/packages/less/package.json
+++ b/packages/less/package.json
@@ -59,6 +59,8 @@
 		"@rollup/plugin-commonjs": "^17.0.0",
 		"@rollup/plugin-json": "^4.1.0",
 		"@rollup/plugin-node-resolve": "^11.0.0",
+		"@typescript-eslint/eslint-plugin": "^4.28.0",
+		"@typescript-eslint/parser": "^4.28.0",
 		"benny": "^3.6.12",
 		"bootstrap-less-port": "0.3.0",
 		"chai": "^4.2.0",

From 8cf010ee3d0b3e4128b135ed3d561dfbbd191f80 Mon Sep 17 00:00:00 2001
From: lumburr <flyfish.zy@foxmail.com>
Date: Tue, 26 Apr 2022 17:13:56 +0800
Subject: [PATCH 3/3] fix: analysis value to fix ESlint warning && fallback
 eslint version

---
 packages/less/package.json                        | 2 +-
 packages/less/src/less/environment/environment.js | 3 +--
 packages/less/src/less/functions/math-helper.js   | 3 +--
 packages/less/src/less/parser/parser.js           | 2 +-
 packages/less/src/less/tree/node.js               | 6 +++---
 packages/less/src/less/tree/quoted.js             | 2 +-
 packages/less/src/less/tree/ruleset.js            | 2 +-
 7 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/packages/less/package.json b/packages/less/package.json
index 1a09a13a9..5976af2f0 100644
--- a/packages/less/package.json
+++ b/packages/less/package.json
@@ -66,7 +66,7 @@
 		"chai": "^4.2.0",
 		"cross-env": "^7.0.3",
 		"diff": "^3.2.0",
-		"eslint": "^8.10.0",
+		"eslint": "^7.29.0",
 		"fs-extra": "^8.1.0",
 		"git-rev": "^0.2.1",
 		"globby": "^10.0.1",
diff --git a/packages/less/src/less/environment/environment.js b/packages/less/src/less/environment/environment.js
index ce85ad6a8..f7d65c6a1 100644
--- a/packages/less/src/less/environment/environment.js
+++ b/packages/less/src/less/environment/environment.js
@@ -4,7 +4,6 @@
  */
 
 import logger from '../logger';
-import * as utils from '../utils';
 
 class Environment {
     constructor(externalEnvironment, fileManagers) {
@@ -31,7 +30,7 @@ class Environment {
         if (!filename) {
             logger.warn('getFileManager called with no filename.. Please report this issue. continuing.');
         }
-        if (utils.isNullOrUndefined(currentDirectory)) {
+        if (currentDirectory === undefined) {
             logger.warn('getFileManager called with null directory.. Please report this issue. continuing.');
         }
 
diff --git a/packages/less/src/less/functions/math-helper.js b/packages/less/src/less/functions/math-helper.js
index e2bebce87..b557875c5 100644
--- a/packages/less/src/less/functions/math-helper.js
+++ b/packages/less/src/less/functions/math-helper.js
@@ -1,11 +1,10 @@
 import Dimension from '../tree/dimension';
-import * as utils from '../utils';
 
 const MathHelper = (fn, unit, n) => {
     if (!(n instanceof Dimension)) {
         throw { type: 'Argument', message: 'argument must be a number' };
     }
-    if (utils.isNullOrUndefined(unit)) {
+    if (unit === null) {
         unit = n.unit;
     } else {
         n = n.unify();
diff --git a/packages/less/src/less/parser/parser.js b/packages/less/src/less/parser/parser.js
index ea3383623..2b2799c62 100644
--- a/packages/less/src/less/parser/parser.js
+++ b/packages/less/src/less/parser/parser.js
@@ -581,7 +581,7 @@ const Parser = function Parser(context, imports, fileInfo) {
 
                     expectChar(')');
 
-                    return new(tree.URL)((!utils.isNullOrUndefined(value.value) || 
+                    return new(tree.URL)((value.value !== undefined || 
                         value instanceof tree.Variable || 
                         value instanceof tree.Property) ?
                         value : new(tree.Anonymous)(value, index), index, fileInfo);
diff --git a/packages/less/src/less/tree/node.js b/packages/less/src/less/tree/node.js
index b2c74aff8..4aadc261c 100644
--- a/packages/less/src/less/tree/node.js
+++ b/packages/less/src/less/tree/node.js
@@ -127,21 +127,21 @@ class Node {
 
     // Returns true if this node represents root of ast imported by reference
     blocksVisibility() {
-        if (utils.isNullOrUndefined(this.visibilityBlocks)) {
+        if (this.visibilityBlocks === undefined) {
             this.visibilityBlocks = 0;
         }
         return this.visibilityBlocks !== 0;
     }
 
     addVisibilityBlock() {
-        if (utils.isNullOrUndefined(this.visibilityBlocks)) {
+        if (this.visibilityBlocks === undefined) {
             this.visibilityBlocks = 0;
         }
         this.visibilityBlocks = this.visibilityBlocks + 1;
     }
 
     removeVisibilityBlock() {
-        if (utils.isNullOrUndefined(this.visibilityBlocks)) {
+        if (this.visibilityBlocks === undefined) {
             this.visibilityBlocks = 0;
         }
         this.visibilityBlocks = this.visibilityBlocks - 1;
diff --git a/packages/less/src/less/tree/quoted.js b/packages/less/src/less/tree/quoted.js
index 20ea852a1..7c96c0ecd 100644
--- a/packages/less/src/less/tree/quoted.js
+++ b/packages/less/src/less/tree/quoted.js
@@ -5,7 +5,7 @@ import * as utils from '../utils';
 
 
 const Quoted = function(str, content, escaped, index, currentFileInfo) {
-    this.escaped = utils.isNullOrUndefined(escaped) ? true : escaped;
+    this.escaped = (escaped === undefined) ? true : escaped;
     this.value = content || '';
     this.quote = str.charAt(0);
     this._index = index;
diff --git a/packages/less/src/less/tree/ruleset.js b/packages/less/src/less/tree/ruleset.js
index fbbe51be3..dfd044932 100644
--- a/packages/less/src/less/tree/ruleset.js
+++ b/packages/less/src/less/tree/ruleset.js
@@ -734,7 +734,7 @@ Ruleset.prototype = Object.assign(new Node(), {
                 // non parent reference elements just get added
                 if (el.value !== '&') {
                     const nestedSelector = findNestedSelector(el);
-                    if (!utils.isNullOrUndefined(nestedSelector)) {
+                    if (nestedSelector !== null) {
                         // merge the current list of non parent selector elements
                         // on to the current list of selectors to add
                         mergeElementsOnToSelectors(currentElements, newSelectors);