refactor(compiler): use `===` rather than `==` in the ml_parser (#42062)

This is a simple tidy up commit to move to the more specific `===`
comparison operator in the HTML lexer/parser.

PR Close #42062

packages/compiler/src/ml_parser/html_tags.ts

@@ -54,7 +54,7 @@ export class HtmlTagDefinition implements TagDefinition {
 
   getContentType(prefix?: string): TagContentType {
     if (typeof this.contentType === 'object') {
-      const overrideType = prefix == null ? undefined : this.contentType[prefix];
+      const overrideType = prefix === undefined ? undefined : this.contentType[prefix];
       return overrideType ?? this.contentType.default;
     }
     return this.contentType;

packages/compiler/src/ml_parser/icu_ast_expander.ts

@@ -80,8 +80,8 @@ class _Expander implements html.Visitor {
 
   visitExpansion(icu: html.Expansion, context: any): any {
     this.isExpanded = true;
-    return icu.type == 'plural' ? _expandPluralForm(icu, this.errors) :
-                                  _expandDefaultForm(icu, this.errors);
+    return icu.type === 'plural' ? _expandPluralForm(icu, this.errors) :
+                                   _expandDefaultForm(icu, this.errors);
   }
 
   visitExpansionCase(icuCase: html.ExpansionCase, context: any): any {
@@ -92,7 +92,7 @@ class _Expander implements html.Visitor {
 // Plural forms are expanded to `NgPlural` and `NgPluralCase`s
 function _expandPluralForm(ast: html.Expansion, errors: ParseError[]): html.Element {
   const children = ast.cases.map(c => {
-    if (PLURAL_CASES.indexOf(c.value) == -1 && !c.value.match(/^=\d+$/)) {
+    if (PLURAL_CASES.indexOf(c.value) === -1 && !c.value.match(/^=\d+$/)) {
       errors.push(new ExpansionError(
           c.valueSourceSpan,
           `Plural cases should be "=<number>" or one of ${PLURAL_CASES.join(', ')}`));

packages/compiler/src/ml_parser/lexer.ts

@@ -881,11 +881,11 @@ function isPrefixEnd(code: number): boolean {
 }
 
 function isDigitEntityEnd(code: number): boolean {
-  return code == chars.$SEMICOLON || code == chars.$EOF || !chars.isAsciiHexDigit(code);
+  return code === chars.$SEMICOLON || code === chars.$EOF || !chars.isAsciiHexDigit(code);
 }
 
 function isNamedEntityEnd(code: number): boolean {
-  return code == chars.$SEMICOLON || code == chars.$EOF || !chars.isAsciiLetter(code);
+  return code === chars.$SEMICOLON || code === chars.$EOF || !chars.isAsciiLetter(code);
 }
 
 function isExpansionCaseStart(peek: number): boolean {
@@ -893,7 +893,7 @@ function isExpansionCaseStart(peek: number): boolean {
 }
 
 function compareCharCodeCaseInsensitive(code1: number, code2: number): boolean {
-  return toUpperCaseCharCode(code1) == toUpperCaseCharCode(code2);
+  return toUpperCaseCharCode(code1) === toUpperCaseCharCode(code2);
 }
 
 function toUpperCaseCharCode(code: number): number {
@@ -905,9 +905,9 @@ function mergeTextTokens(srcTokens: Token[]): Token[] {
   let lastDstToken: Token|undefined = undefined;
   for (let i = 0; i < srcTokens.length; i++) {
     const token = srcTokens[i];
-    if ((lastDstToken && lastDstToken.type == TokenType.TEXT && token.type == TokenType.TEXT) ||
-        (lastDstToken && lastDstToken.type == TokenType.ATTR_VALUE_TEXT &&
-         token.type == TokenType.ATTR_VALUE_TEXT)) {
+    if ((lastDstToken && lastDstToken.type === TokenType.TEXT && token.type === TokenType.TEXT) ||
+        (lastDstToken && lastDstToken.type === TokenType.ATTR_VALUE_TEXT &&
+         token.type === TokenType.ATTR_VALUE_TEXT)) {
       lastDstToken.parts[0]! += token.parts[0];
       lastDstToken.sourceSpan.end = token.sourceSpan.end;
     } else {

packages/compiler/src/ml_parser/parser.ts

@@ -187,7 +187,7 @@ class _TreeBuilder {
       if (this._peek.type === TokenType.EXPANSION_CASE_EXP_END) {
         if (lastOnStack(expansionFormStack, TokenType.EXPANSION_CASE_EXP_START)) {
           expansionFormStack.pop();
-          if (expansionFormStack.length == 0) return exp;
+          if (expansionFormStack.length === 0) return exp;
 
         } else {
           this.errors.push(
@@ -220,9 +220,9 @@ class _TreeBuilder {
     const tokens = [token];
     const startSpan = token.sourceSpan;
     let text = token.parts[0];
-    if (text.length > 0 && text[0] == '\n') {
+    if (text.length > 0 && text[0] === '\n') {
       const parent = this._getParentElement();
-      if (parent != null && parent.children.length == 0 &&
+      if (parent != null && parent.children.length === 0 &&
           this.getTagDefinition(parent.name).ignoreFirstLf) {
         text = text.substring(1);
         tokens[0] = {type: token.type, sourceSpan: token.sourceSpan, parts: [text]} as typeof token;
@@ -342,7 +342,7 @@ class _TreeBuilder {
     let unexpectedCloseTagDetected = false;
     for (let stackIndex = this._elementStack.length - 1; stackIndex >= 0; stackIndex--) {
       const el = this._elementStack[stackIndex];
-      if (el.name == fullName) {
+      if (el.name === fullName) {
         // Record the parse span with the element that is being closed. Any elements that are
         // removed from the element stack at this point are closed implicitly, so they won't get
         // an end source span (as there is no explicit closing element).

packages/compiler/src/ml_parser/tags.ts

@@ -31,7 +31,7 @@ export function splitNsName(elementName: string): [string|null, string] {
 
   const colonIndex = elementName.indexOf(':', 1);
 
-  if (colonIndex == -1) {
+  if (colonIndex === -1) {
     throw new Error(`Unsupported format "${elementName}" expecting ":namespace:name"`);
   }