how do I fix runtime error Unexpected token ':'-CodePudding

A sample project in typescript and vscode (Windows 11)

This is my app.ts code

function add(n1: number, n2:number) {
  return n1   n2;
}

const number1 = 5;
const number2 = 2.8;

const result = add(number1, number2);
console.log(result);

evrything compiles with no errors

But when I click on Run|Run Without Debbugging, I get this error

Uncaught SyntaxError g:\TypeScript\TS_4\2_Types\010_basics-1\app.ts:2
function add(n1: number, n2:number) {
               ^

SyntaxError: Unexpected token ':'
    at compileFunction (undefined:352:18)
    at wrapSafe (undefined:1033:15)
    at Module._compile (undefined:1069:27)
    at Module._extensions..js (undefined:1159:10)
    at Module.load (undefined:981:32)
    at Module._load (undefined:822:12)
    at executeUserEntryPoint (undefined:77:12)
    at <anonymous> (undefined:17:47)

This my index.html file

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Understanding TypeScript</title>
    <script src="app.js" defer></script>
  </head>
  <body>
  
  </body>
</html>

when I run the html file, there is no bug, abd the expected result apperas in the console

CodePudding user response：

You can't just run a TS file.

The error you are getting is because a TS file is not a valid JS file because of the type definitions !

Make sure you follow the procedure described here:

Define a .tsconfig

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "outDir": "out",
    "sourceMap": true
  }
}

and setup your launch.json:

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "node",
      "request": "launch",
      "name": "Launch Program",
      "program": "${workspaceFolder}/helloworld.ts",
      "preLaunchTask": "tsc: build - tsconfig.json",
      "outFiles": ["${workspaceFolder}/out/**/*.js"]
    }
  ]
}

CodePudding user response：

You need a space between n2 and number?

I strongly suggest you to get full support from the editor while coding.