Remove use of deprecated String.substr from the JS compiler. NFC (#23512)

Author: sbc100

src/jsifier.mjs

@@ -51,7 +51,7 @@ function mangleCSymbolName(f) {
   if (f === '__main_argc_argv') {
     f = 'main';
   }
-  return f[0] == '$' ? f.substr(1) : '_' + f;
+  return f[0] == '$' ? f.slice(1) : '_' + f;
 }
 
 // Splits out items that pass filter. Returns also the original sans the filtered
@@ -284,7 +284,7 @@ ${argConversions}
 
     // apply LIBRARY_DEBUG if relevant
     if (LIBRARY_DEBUG && !isJsOnlySymbol(symbol)) {
-      snippet = modifyJSFunction(snippet, (args, body, async, oneliner) => {
+      snippet = modifyJSFunction(snippet, (args, body, _async, oneliner) => {
         var run_func;
         if (oneliner) {
           run_func = `var ret = ${body}`;
@@ -637,7 +637,7 @@ function(${args}) {
         //  emits
         //   'var foo = [value];'
         if (typeof snippet == 'string' && snippet[0] == '=') {
-          snippet = snippet.substr(1);
+          snippet = snippet.slice(1);
         }
         contentText = `var ${mangled} = ${snippet};`;
       }

src/modules.mjs

@@ -374,7 +374,7 @@ function getUnusedLibrarySymbols() {
   for (const [ident, value] of Object.entries(LibraryManager.library)) {
     if (typeof value === 'function' || typeof value === 'number') {
       if (isJsOnlySymbol(ident) && !isDecorator(ident) && !isInternalSymbol(ident)) {
-        const name = ident.substr(1);
+        const name = ident.slice(1);
         if (!librarySymbolSet.has(name)) {
           missingSyms.add(name);
         }
@@ -492,7 +492,7 @@ function exportRuntime() {
   let runtimeElementsSet = new Set(runtimeElements);
   for (const ident of Object.keys(LibraryManager.library)) {
     if (isJsOnlySymbol(ident) && !isDecorator(ident) && !isInternalSymbol(ident)) {
-      const jsname = ident.substr(1);
+      const jsname = ident.slice(1);
       // Note that this assertion may be hit when a function is moved into the
       // JS library. In that case the function should be removed from the list
       // of runtime elements above.

src/parseTools.mjs

@@ -141,9 +141,9 @@ export function preprocess(filename) {
           showStack.push(truthy ? SHOW : IGNORE);
         } else if (first === '#include') {
           if (showCurrentLine()) {
-            let includeFile = line.substr(line.indexOf(' ') + 1);
+            let includeFile = line.slice(line.indexOf(' ') + 1);
             if (includeFile.startsWith('"')) {
-              includeFile = includeFile.substr(1, includeFile.length - 2);
+              includeFile = includeFile.slice(1, -1);
             }
             const absPath = findIncludeFile(includeFile, path.dirname(filename));
             if (!absPath) {
@@ -328,7 +328,7 @@ function getNativeTypeSize(type) {
         return POINTER_SIZE;
       }
       if (type[0] === 'i') {
-        const bits = Number(type.substr(1));
+        const bits = Number(type.slice(1));
         assert(bits % 8 === 0, `getNativeTypeSize invalid bits ${bits}, ${type} type`);
         return bits / 8;
       }
@@ -360,7 +360,7 @@ function ensureDot(value) {
   if (value.includes('.') || /[IN]/.test(value)) return value;
   const e = value.indexOf('e');
   if (e < 0) return value + '.0';
-  return value.substr(0, e) + '.0' + value.substr(e);
+  return value.slice(0, e) + '.0' + value.slice(e);
 }
 
 export function isNumber(x) {
@@ -406,7 +406,7 @@ function asmFloatToInt(x) {
 }
 
 // See makeSetValue
-function makeGetValue(ptr, pos, type, noNeedFirst, unsigned, ignore, align) {
+function makeGetValue(ptr, pos, type, noNeedFirst, unsigned, _ignore, align) {
   assert(typeof align === 'undefined', 'makeGetValue no longer supports align parameter');
   assert(
     typeof noNeedFirst === 'undefined',
@@ -551,7 +551,7 @@ function getFastValue(a, op, b) {
 
   if (b[0] === '-') {
     op = '-';
-    b = b.substr(1);
+    b = b.slice(1);
   }
 
   return `(${a})${op}(${b})`;
@@ -785,14 +785,14 @@ export function modifyJSFunction(text, func) {
   if (match) {
     async_ = match[1] || '';
     args = match[3];
-    rest = text.substr(match[0].length);
+    rest = text.slice(match[0].length);
   } else {
     // Match an arrow function
     let match = text.match(/^\s*(var (\w+) = )?(async\s+)?\(([^)]*)\)\s+=>\s+/);
     if (match) {
       async_ = match[3] || '';
       args = match[4];
-      rest = text.substr(match[0].length);
+      rest = text.slice(match[0].length);
       rest = rest.trim();
       oneliner = rest[0] != '{';
     } else {
@@ -802,7 +802,7 @@ export function modifyJSFunction(text, func) {
       assert(match, `could not match function:\n${text}\n`);
       async_ = match[1] || '';
       args = match[2];
-      rest = text.substr(match[0].length);
+      rest = text.slice(match[0].length);
     }
   }
   let body = rest;

tools/acorn-optimizer.mjs

@@ -2023,7 +2023,7 @@ const input = read(infile);
 const extraInfoStart = input.lastIndexOf('// EXTRA_INFO:');
 let extraInfo = null;
 if (extraInfoStart > 0) {
-  extraInfo = JSON.parse(input.substr(extraInfoStart + 14));
+  extraInfo = JSON.parse(input.slice(extraInfoStart + 14));
 }
 // Collect all JS code comments to this map so that we can retain them in the
 // outputted code if --closureFriendly was requested.