New command line help developer experience.

src/compiler/diagnosticMessages.json

@@ -4031,11 +4031,11 @@
         "category": "Message",
         "code": 6014
     },
-    "Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', 'ES2021', or 'ESNEXT'.": {
+    "Specify ECMAScript target version.": {
         "category": "Message",
         "code": 6015
     },
-    "Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'.": {
+    "Specify module code generation.": {
         "category": "Message",
         "code": 6016
     },
@@ -4243,7 +4243,7 @@
         "category": "Message",
         "code": 6079
     },
-    "Specify JSX code generation: 'preserve', 'react-native', 'react', 'react-jsx' or 'react-jsxdev'.": {
+    "Specify JSX code generation.": {
         "category": "Message",
         "code": 6080
     },
@@ -5638,6 +5638,127 @@
         "code": 6803
     },
 
+    "one of:": {
+        "category": "Message",
+        "code": 6900
+    },
+    "one or more:": {
+        "category": "Message",
+        "code": 6901
+    },
+    "type:": {
+        "category": "Message",
+        "code": 6902
+    },
+    "default:": {
+        "category": "Message",
+        "code": 6903
+    },
+    "module === \"system\" or esModuleInterop": {
+        "category": "Message",
+        "code": 6904
+    },
+    "`false`, unless `strict` is set": {
+        "category": "Message",
+        "code": 6905
+    },
+    "`false`, unless `composite` is set": {
+        "category": "Message",
+        "code": 6906
+    },
+    "`[\"node_modules\", \"bower_components\", \"jspm_packages\"]`, plus the value of `outDir` if one is specified.": {
+        "category": "Message",
+        "code": 6907
+    },
+    "`[]` if `files` is specified, otherwise `[\"**/*\"]`": {
+        "category": "Message",
+        "code": 6908
+    },
+    "`true` if `composite`, `false` otherwise": {
+        "category": "Message",
+        "code": 6909
+    },
+    "module === `AMD` or `UMD` or `System` or `ES6`, then `Classic`, Otherwise `Node`": {
+        "category": "Message",
+        "code": 69010
+    },
+    "Computed from the list of input files": {
+        "category": "Message",
+        "code": 6911
+    },
+    "Platform specific": {
+        "category": "Message",
+        "code": 6912
+    },
+    "You can learn about all of the compiler options at {0}": {
+        "category": "Message",
+        "code": 6913
+    },
+    "Including --watch, -w will start watching the current project for the file changes. Once set, you can config watch mode with:": {
+        "category": "Message",
+        "code": 6914
+    },
+    "Using --build, -b will make tsc behave more like a build orchestrator than a compiler. This is used to trigger building composite projects which you can learn more about at {0}": {
+        "category": "Message",
+        "code": 6915
+    },
+    "COMMON COMMANDS": {
+        "category": "Message",
+        "code": 6916
+    },
+    "ALL COMPILER OPTIONS": {
+        "category": "Message",
+        "code": 6917
+    },
+    "WATCH OPTIONS": {
+        "category": "Message",
+        "code": 6918
+    },
+    "BUILD OPTIONS": {
+        "category": "Message",
+        "code": 6919
+    },
+    "COMMON COMPILER OPTIONS": {
+        "category": "Message",
+        "code": 6920
+    },
+    "COMMAND LINE FLAGS": {
+        "category": "Message",
+        "code": 6921
+    },
+    "tsc: The TypeScript Compiler": {
+        "category": "Message",
+        "code": 6922
+    },
+    "Compiles the current project (tsconfig.json in the working directory.)": {
+        "category": "Message",
+        "code": 6923
+    },
+    "Ignoring tsconfig.json, compiles the specified files with default compiler options": {
+        "category": "Message",
+        "code": 6924
+    },
+    "Build a composite project in the working directory.": {
+        "category": "Message",
+        "code": 6925
+    },
+    "Creates a tsconfig.json with the recommended settings in the working directory.": {
+        "category": "Message",
+        "code": 6926
+    },
+    "Compiles the TypeScript project located at the specified path": {
+        "category": "Message",
+        "code": 6927
+    },
+    "An expanded version of this information, showing all possible compiler options": {
+        "category": "Message",
+        "code": 6928
+    },
+    "Compiles the current project, with additional settings": {
+        "category": "Message",
+        "code": 6929
+    },
+
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005

src/compiler/sys.ts

@@ -1162,6 +1162,7 @@ namespace ts {
         useCaseSensitiveFileNames: boolean;
         write(s: string): void;
         writeOutputIsTTY?(): boolean;
+        getWidthOfTerminal?(): number;
         readFile(path: string, encoding?: string): string | undefined;
         getFileSize?(path: string): number;
         writeFile(path: string, data: string, writeByteOrderMark?: boolean): void;
@@ -1308,6 +1309,9 @@ namespace ts {
                 write(s: string): void {
                     process.stdout.write(s);
                 },
+                getWidthOfTerminal(){
+                    return process.stdout.columns;
+                },
                 writeOutputIsTTY() {
                     return process.stdout.isTTY;
                 },

src/compiler/types.ts

@@ -6224,7 +6224,8 @@ namespace ts {
         type: "string" | "number" | "boolean" | "object" | "list" | ESMap<string, number | string>;    // a value of a primitive type, or an object literal mapping named values to actual values
         isFilePath?: boolean;                                   // True if option value is a path or fileName
         shortName?: string;                                     // A short mnemonic for convenience - for instance, 'h' can be used in place of 'help'
-        description?: DiagnosticMessage;                        // The message describing what the command line switch does
+        description?: DiagnosticMessage;                        // The message describing what the command line switch does.
+        defaultValueDescription?: string | DiagnosticMessage;   // The message describing what the dafault value is. string type is prepared for fixed chosen like "false" which do not need I18n.
         paramType?: DiagnosticMessage;                          // The name to be used for a non-boolean option's parameter
         isTSConfigOnly?: boolean;                               // True if option can only be specified via tsconfig.json file
         isCommandLineOnly?: boolean;