All TypeScript 2.3 options for tsconfig.json (tsc --init) | José Quinto

Introduction

Yesterday was released TypeScript 2.3 and one of the improvements was an easier startup with better help, richer init, and quicker strictness.

It means that TypeScript’s --init output so that potential options are explicitly listed out in comments. As an example, tsconfig.json output will look something like the following:

	{
	"compilerOptions": {
	/* Basic Options */
	"target": "es5", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'. */
	"module": "commonjs", /* Specify module code generation: 'commonjs', 'amd', 'system', 'umd' or 'es2015'. */
	"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. */
	"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. */
	/* 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. */
	}
	}

view raw JQ.TypeScript.Init.Options.json.js hosted with ❤ by GitHub

We can see how TypeScript team added a new flag called “strict” which is activated by default when create “tsc –init”.

--strict flag, which enables the following settings

• --noImplicitAny
• --strictNullChecks
• --noImplicitThis
• --alwaysStrict (which enforces JavaScript strict mode in all files) This --strict flag represents a set of flags that the TypeScript team believes will lead to the most optimal developer experience in using the language.

You can see the full options in the official wiki page as well.

Read more…

You can read the full list of what’s new in TypeScript and read TypeScript’s Roadmap to see what’s coming in the future!