Add types for String#isWellFormed and String#toWellFormed

src/compiler/commandLineParser.ts

@@ -236,6 +236,7 @@ const libEntries: [string, string][] = [
     ["esnext.object", "lib.esnext.object.d.ts"],
     ["esnext.array", "lib.esnext.array.d.ts"],
     ["esnext.regexp", "lib.esnext.regexp.d.ts"],
+    ["esnext.string", "lib.esnext.string.d.ts"],
     ["decorators", "lib.decorators.d.ts"],
     ["decorators.legacy", "lib.decorators.legacy.d.ts"],
 ];

src/compiler/utilities.ts

@@ -1507,6 +1507,10 @@ export const getScriptTargetFeatures = /* @__PURE__ */ memoize((): ScriptTargetF
             es2022: [
                 "at",
             ],
+            esnext: [
+                "isWellFormed",
+                "toWellFormed",
+            ],
         })),
         StringConstructor: new Map(Object.entries({
             es2015: [

src/lib/esnext.d.ts

@@ -7,3 +7,4 @@
 /// <reference lib="esnext.collection" />
 /// <reference lib="esnext.array" />
 /// <reference lib="esnext.regexp" />
+/// <reference lib="esnext.string" />

src/lib/esnext.string.d.ts

@@ -0,0 +1,11 @@
+interface String {
+    /**
+     * Returns true if all leading surrogates and trailing surrogates appear paired and in order.
+     */
+    isWellFormed(): boolean;
+
+    /**
+     * Returns a string where all lone or out-of-order surrogates have been replaced by the Unicode replacement character (U+FFFD).
+     */
+    toWellFormed(): string;
+}

src/lib/libs.json

@@ -79,6 +79,7 @@
         "esnext.collection",
         "esnext.array",
         "esnext.regexp",
+        "esnext.string",
         "decorators",
         "decorators.legacy",
         // Default libraries

tests/baselines/reference/bundlerDirectoryModule(moduleresolution=bundler).trace.json

@@ -1074,6 +1074,21 @@
     "======== Module name '@typescript/lib-esnext/regexp' was not resolved. ========",
     "File '/.ts/package.json' does not exist according to earlier cached lookups.",
     "File '/package.json' does not exist according to earlier cached lookups.",
+    "======== Resolving module '@typescript/lib-esnext/string' from '/.src/__lib_node_modules_lookup_lib.esnext.string.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-esnext/string' was not resolved. ========",
+    "File '/.ts/package.json' does not exist according to earlier cached lookups.",
+    "File '/package.json' does not exist according to earlier cached lookups.",
     "======== Resolving module '@typescript/lib-dom' from '/.src/__lib_node_modules_lookup_lib.dom.d.ts__.ts'. ========",
     "Explicitly specified module resolution kind: 'Node10'.",
     "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: TypeScript, Declaration.",

tests/baselines/reference/bundlerDirectoryModule(moduleresolution=nodenext).trace.json

@@ -1074,6 +1074,21 @@
     "======== Module name '@typescript/lib-esnext/regexp' was not resolved. ========",
     "File '/.ts/package.json' does not exist according to earlier cached lookups.",
     "File '/package.json' does not exist according to earlier cached lookups.",
+    "======== Resolving module '@typescript/lib-esnext/string' from '/.src/__lib_node_modules_lookup_lib.esnext.string.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-esnext/string' was not resolved. ========",
+    "File '/.ts/package.json' does not exist according to earlier cached lookups.",
+    "File '/package.json' does not exist according to earlier cached lookups.",
     "======== Resolving module '@typescript/lib-dom' from '/.src/__lib_node_modules_lookup_lib.dom.d.ts__.ts'. ========",
     "Explicitly specified module resolution kind: 'Node10'.",
     "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: TypeScript, Declaration.",

tests/baselines/reference/dependentDestructuredVariablesFromNestedPatterns.symbols

@@ -70,7 +70,7 @@ async function myAllSettled<T extends readonly unknown[]>(fn: () => T) {
       : [undefined, new Error(String(result.reason))],
 >undefined : Symbol(undefined)
 >Error : Symbol(Error, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2022.error.d.ts, --, --))
->String : Symbol(String, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --) ... and 6 more)
+>String : Symbol(String, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --) ... and 7 more)
 >result.reason : Symbol(PromiseRejectedResult.reason, Decl(lib.es2020.promise.d.ts, --, --))
 >result : Symbol(result, Decl(dependentDestructuredVariablesFromNestedPatterns.ts, 21, 23))
 >reason : Symbol(PromiseRejectedResult.reason, Decl(lib.es2020.promise.d.ts, --, --))

tests/baselines/reference/modulePreserve2.trace.json

@@ -1019,6 +1019,20 @@
     "======== Module name '@typescript/lib-esnext/regexp' was not resolved. ========",
     "File '/.ts/package.json' does not exist according to earlier cached lookups.",
     "File '/package.json' does not exist according to earlier cached lookups.",
+    "======== Resolving module '@typescript/lib-esnext/string' from '/.src/__lib_node_modules_lookup_lib.esnext.string.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-esnext/string' was not resolved. ========",
+    "File '/.ts/package.json' does not exist according to earlier cached lookups.",
+    "File '/package.json' does not exist according to earlier cached lookups.",
     "======== Resolving module '@typescript/lib-dom' from '/.src/__lib_node_modules_lookup_lib.dom.d.ts__.ts'. ========",
     "Explicitly specified module resolution kind: 'Node10'.",
     "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: TypeScript, Declaration.",

tests/baselines/reference/modulePreserve3.trace.json

@@ -951,6 +951,19 @@
     "======== Module name '@typescript/lib-esnext/regexp' was not resolved. ========",
     "File '/.ts/package.json' does not exist according to earlier cached lookups.",
     "File '/package.json' does not exist according to earlier cached lookups.",
+    "======== Resolving module '@typescript/lib-esnext/string' from '/.src/__lib_node_modules_lookup_lib.esnext.string.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-esnext/string' was not resolved. ========",
+    "File '/.ts/package.json' does not exist according to earlier cached lookups.",
+    "File '/package.json' does not exist according to earlier cached lookups.",
     "======== Resolving module '@typescript/lib-dom' from '/.src/__lib_node_modules_lookup_lib.dom.d.ts__.ts'. ========",
     "Explicitly specified module resolution kind: 'Node10'.",
     "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: TypeScript, Declaration.",

tests/baselines/reference/nodeModulesExportsBlocksTypesVersions(module=nodenext).trace.json

@@ -1189,6 +1189,20 @@
     "======== Module name '@typescript/lib-esnext/regexp' was not resolved. ========",
     "File '/.ts/package.json' does not exist according to earlier cached lookups.",
     "File '/package.json' does not exist according to earlier cached lookups.",
+    "======== Resolving module '@typescript/lib-esnext/string' from '/.src/__lib_node_modules_lookup_lib.esnext.string.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-esnext/string' was not resolved. ========",
+    "File '/.ts/package.json' does not exist according to earlier cached lookups.",
+    "File '/package.json' does not exist according to earlier cached lookups.",
     "======== Resolving module '@typescript/lib-dom' from '/.src/__lib_node_modules_lookup_lib.dom.d.ts__.ts'. ========",
     "Explicitly specified module resolution kind: 'Node10'.",
     "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: TypeScript, Declaration.",

tests/baselines/reference/nodeModulesPackageImports(module=nodenext).trace.json

@@ -1133,6 +1133,21 @@
     "======== Module name '@typescript/lib-esnext/regexp' was not resolved. ========",
     "File '/.ts/package.json' does not exist according to earlier cached lookups.",
     "File '/package.json' does not exist according to earlier cached lookups.",
+    "======== Resolving module '@typescript/lib-esnext/string' from '/.src/__lib_node_modules_lookup_lib.esnext.string.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/.src/node_modules' does not exist, skipping all lookups in it.",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-esnext/string' was not resolved. ========",
+    "File '/.ts/package.json' does not exist according to earlier cached lookups.",
+    "File '/package.json' does not exist according to earlier cached lookups.",
     "======== Resolving module '@typescript/lib-dom' from '/.src/__lib_node_modules_lookup_lib.dom.d.ts__.ts'. ========",
     "Explicitly specified module resolution kind: 'Node10'.",
     "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: TypeScript, Declaration.",

tests/baselines/reference/nodeModulesPackagePatternExportsTrailers(module=nodenext).trace.json

@@ -1170,6 +1170,20 @@
     "======== Module name '@typescript/lib-esnext/regexp' was not resolved. ========",
     "File '/.ts/package.json' does not exist according to earlier cached lookups.",
     "File '/package.json' does not exist according to earlier cached lookups.",
+    "======== Resolving module '@typescript/lib-esnext/string' from '/.src/__lib_node_modules_lookup_lib.esnext.string.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Directory '/.src/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-esnext/string' was not resolved. ========",
+    "File '/.ts/package.json' does not exist according to earlier cached lookups.",
+    "File '/package.json' does not exist according to earlier cached lookups.",
     "======== Resolving module '@typescript/lib-dom' from '/.src/__lib_node_modules_lookup_lib.dom.d.ts__.ts'. ========",
     "Explicitly specified module resolution kind: 'Node10'.",
     "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: TypeScript, Declaration.",

tests/baselines/reference/reactJsxReactResolvedNodeNext.trace.json

@@ -964,6 +964,19 @@
     "======== Module name '@typescript/lib-esnext/regexp' was not resolved. ========",
     "File '/.ts/package.json' does not exist according to earlier cached lookups.",
     "File '/package.json' does not exist according to earlier cached lookups.",
+    "======== Resolving module '@typescript/lib-esnext/string' from '/.src/__lib_node_modules_lookup_lib.esnext.string.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-esnext/string' was not resolved. ========",
+    "File '/.ts/package.json' does not exist according to earlier cached lookups.",
+    "File '/package.json' does not exist according to earlier cached lookups.",
     "======== Resolving module '@typescript/lib-dom' from '/.src/__lib_node_modules_lookup_lib.dom.d.ts__.ts'. ========",
     "Explicitly specified module resolution kind: 'Node10'.",
     "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: TypeScript, Declaration.",

tests/baselines/reference/reactJsxReactResolvedNodeNextEsm.trace.json

@@ -964,6 +964,19 @@
     "======== Module name '@typescript/lib-esnext/regexp' was not resolved. ========",
     "File '/.ts/package.json' does not exist according to earlier cached lookups.",
     "File '/package.json' does not exist according to earlier cached lookups.",
+    "======== Resolving module '@typescript/lib-esnext/string' from '/.src/__lib_node_modules_lookup_lib.esnext.string.d.ts__.ts'. ========",
+    "Explicitly specified module resolution kind: 'Node10'.",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: TypeScript, Declaration.",
+    "Searching all ancestor node_modules directories for preferred extensions: TypeScript, Declaration.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "Scoped package detected, looking in 'typescript__lib-esnext/string'",
+    "Loading module '@typescript/lib-esnext/string' from 'node_modules' folder, target file types: JavaScript.",
+    "Searching all ancestor node_modules directories for fallback extensions: JavaScript.",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name '@typescript/lib-esnext/string' was not resolved. ========",
+    "File '/.ts/package.json' does not exist according to earlier cached lookups.",
+    "File '/package.json' does not exist according to earlier cached lookups.",
     "======== Resolving module '@typescript/lib-dom' from '/.src/__lib_node_modules_lookup_lib.dom.d.ts__.ts'. ========",
     "Explicitly specified module resolution kind: 'Node10'.",
     "Loading module '@typescript/lib-dom' from 'node_modules' folder, target file types: TypeScript, Declaration.",