Including .js files with —allowJs

Often there are external source files in your project that may not be authored in TypeScript.Alternatively, you might be in the middle of converting a JS code base into TS, but still want to bundle all your JS code into a single file with the output of your new TS code.

.js files are now allowed as input to tsc.The TypeScript compiler checks the input .js files for syntax errors, and emits valid output based on the —target and —module flags.The output can be combined with other .ts files as well.Source maps are still generated for .js files just like with .ts files.