TypeScript Compiler Configuration | tsconfig.json file example

tsc --init  

{  
  "compilerOptions": {  
    /* Basic Options */  
    "target": "es5",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */  
    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */  
    // "lib": [],                             /* Specify library files to be included in the compilation. */  
    // "allowJs": true,                       /* Allow javascript files to be compiled. */  
    // "checkJs": true,                       /* Report errors in .js files. */  
    // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */  
    // "declaration": true,                   /* Generates corresponding '.d.ts' file. */  
    // "sourceMap": true,                     /* Generates corresponding '.map' file. */  
    // "outFile": "./",                       /* Concatenate and emit output to single file. */  
    // "outDir": "./",                        /* Redirect output structure to the directory. */  
    // "rootDir": "./",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */  
    // "removeComments": true,                /* Do not emit comments to output. */  
    // "noEmit": true,                        /* Do not emit outputs. */  
    // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */  
    // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */  
    // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */  
  
    /* Strict Type-Checking Options */  
    "strict": true,                           /* Enable all strict type-checking options. */  
    // "noImplicitAny": true,                 /* Raise error on expressions and declarations with an implied 'any' type. */  
    // "strictNullChecks": true,              /* Enable strict null checks. */  
    // "strictFunctionTypes": true,           /* Enable strict checking of function types. */  
    // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */  
    // "noImplicitThis": true,                /* Raise error on 'this' expressions with an implied 'any' type. */  
    // "alwaysStrict": true,                  /* Parse in strict mode and emit "use strict" for each source file. */  
  
    /* Additional Checks */  
    // "noUnusedLocals": true,                /* Report errors on unused locals. */  
    // "noUnusedParameters": true,            /* Report errors on unused parameters. */  
    // "noImplicitReturns": true,             /* Report error when not all code paths in function return a value. */  
    // "noFallthroughCasesInSwitch": true,    /* Report errors for fallthrough cases in switch statement. */  
  
    /* Module Resolution Options */  
    // "moduleResolution": "node",            /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */  
    // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */  
    // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */  
    // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */  
    // "typeRoots": [],                       /* List of folders to include type definitions from. */  
    // "types": [],                           /* Type declaration files to be included in compilation. */  
    // "allowSyntheticDefaultImports": true,  /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */  
    "esModuleInterop": true                   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */  
    // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */  
  
    /* Source Map Options */  
    // "sourceRoot": "./",                    /* Specify the location where debugger should locate TypeScript files instead of source locations. */  
    // "mapRoot": "./",                       /* Specify the location where debugger should locate map files instead of generated locations. */  
    // "inlineSourceMap": true,               /* Emit a single file with source maps instead of having a separate file. */  
    // "inlineSources": true,                 /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */  
  
    /* Experimental Options */  
    // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */  
    // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */  
  }  
}  

let numberVariable: number = 45;  
numberVariable = null; // no issues  
numberVariable = undefined; // no issues  

let numberVariable = undefined;  
numberVariable = null; // As undefined and null are different  

{  
    "include": [  
        "src/main/webapp/app",  
        "src/main/webapp/app/app.main.ts",  
        "src/test/javascript/"  
    ],  
    exclude": [  
        "node_modules",  
    ]  
}