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    /* Type Checking */
    "strict": true /* Enable all strict type-checking options. */,
    // "noImplicitAny": true,                            /* Enable error reporting for expressions and declarations with an implied `any` type.. */
    // "strictNullChecks": true,                         /* When type checking, take into account `null` and `undefined`. */
    // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
    // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
    // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
    // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
    // "useUnknownInCatchVariables": true,               /* Type catch clause 

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"target": "ES6" /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */,
"lib": [
  "DOM",
  "ES6",
  "DOM.Iterable",
  "ScriptHost"
] 
/* Specify a set of bundled library declaration files that describe the target runtime environment. */

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"compilerOptions": {
........
........
},
"exclude": [
    "node_module",
    // "analytics.ts"
  ],
  "include": [
    "app.ts",

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// Utility function which build error function
function generateError(message: string, code: number): never {
  throw { message, errorCode: code };
}

generateError('An error occured', 500);

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let userInput: unknown;
let userName: string;

userInput = 5; // OK
userInput = 'Max'; // OK
// userName = userInput; // KO – Type 'unknown' is not assignable to type 'string'.


if (typeof userInput === 'string') {
  userName = userInput;

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// callback
function addAndHandle(n1: number, n2: number, cb: (num: number) => void) {
  const result = n1 + n2;
  cb(result);
}
addAndHandle(1, 3, (result) => {
  console.log(result);
});

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// number return type
function addFunction(n1: number, n2: number): number {
  return n1 + n2;
}

// void return type
function printResultFunction(num: number): void {
  console.log('Result: ' + num);
}

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

// void return type
function printResult(num: number): void {
  console.log('Result: ' + num);
}

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type Whatever = number; // it works but we should avoir it
type Combinable = number | string; // a new type we're creating based on a union type
type ConversionDescriptor = 'as-number' | 'as-text'; // a new type we're creating based on a literal type

function combineAliaces(
  input1: Whatever | string,
  input2: Combinable,
  resultConversion: ConversionDescriptor,
) {
  let result;

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function combine(
  input1: number | string,
  input2: number | string,
  resultConversion: 'as-number' | 'as-text', // literal type
) {
  let result;
  if (typeof input1 === 'number' && typeof input2 === 'number') {
    result = input1 + input2;
  } else {
    result = input1.toString() + input2.toString();