Is any JavaScript code a valid TypeScript code?

Question

Currently I\'ve started to learn TypeScript. From the documents I\'ve studied for TypeScript, I saw some samples that pure JavaScript

Answer 1

Not any valid JavaScript code is valid TypeScript see my example below.

var testVar = 4;
testVar = "asdf";

TypeScript gives the following error: Cannot convert string to number. To make that work in TypeScript add ":any" like below.

var testVar: any = 4;
testVar = "asdf"

This happens because TypeScript noticed testVar is declared and in the declaration it is assigned a number and therefore it decides it should stay a number.