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TypeScript 5.x in 2025: Essential Features Every Developer Should Know

TypeScript 5.x brings powerful new features that improve developer productivity and code quality. Explore the most impactful additions to the language.

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TypeScript 5.x in 2025: Essential Features Every Developer Should Know

TypeScript 5.x represents a significant evolution of the language, introducing features that make code more expressive, safer, and easier to maintain. Let's explore the most impactful additions that should be in every developer's toolkit.

Decorators (Stage 3)

TypeScript 5.0 added support for the ECMAScript decorators proposal, enabling cleaner metaprogramming:

<span class="hljs-keyword">function</span> <span class="hljs-title function_">logged</span>(<span class="hljs-params"><span class="hljs-attr">target</span>: <span class="hljs-built_in">any</span>, <span class="hljs-attr">context</span>: <span class="hljs-title class_">ClassMethodDecoratorContext</span></span>) {
  <span class="hljs-keyword">const</span> methodName = <span class="hljs-title class_">String</span>(context.<span class="hljs-property">name</span>);

  <span class="hljs-keyword">return</span> <span class="hljs-keyword">function</span>(<span class="hljs-params"><span class="hljs-attr">this</span>: <span class="hljs-built_in">any</span>, ...<span class="hljs-attr">args</span>: <span class="hljs-built_in">any</span>[]</span>) {
    <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`Calling <span class="hljs-subst">${methodName}</span> with:`</span>, args);
    <span class="hljs-keyword">const</span> result = target.<span class="hljs-title function_">call</span>(<span class="hljs-variable language_">this</span>, ...args);
    <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">`Result:`</span>, result);
    <span class="hljs-keyword">return</span> result;
  };
}

<span class="hljs-keyword">class</span> <span class="hljs-title class_">Calculator</span> {
  <span class="hljs-meta">@logged</span>
  <span class="hljs-title function_">add</span>(<span class="hljs-params"><span class="hljs-attr">a</span>: <span class="hljs-built_in">number</span>, <span class="hljs-attr">b</span>: <span class="hljs-built_in">number</span></span>) {
    <span class="hljs-keyword">return</span> a + b;
  }
}

<span class="hljs-keyword">const</span> calc = <span class="hljs-keyword">new</span> <span class="hljs-title class_">Calculator</span>();
calc.<span class="hljs-title function_">add</span>(<span class="hljs-number">2</span>, <span class="hljs-number">3</span>);
<span class="hljs-comment">// Logs: Calling add with: [2, 3]</span>
<span class="hljs-comment">// Logs: Result: 5</span>

Use Cases

Dependency Injection:

<span class="hljs-keyword">class</span> <span class="hljs-title class_">UserService</span> {
  <span class="hljs-meta">@inject</span>(<span class="hljs-title class_">DatabaseService</span>)
  <span class="hljs-keyword">private</span> db!: <span class="hljs-title class_">DatabaseService</span>;
}

Validation:

<span class="hljs-keyword">class</span> <span class="hljs-title class_">User</span> {
  <span class="hljs-meta">@validate</span>
  <span class="hljs-meta">@length</span>(<span class="hljs-number">3</span>, <span class="hljs-number">20</span>)
  username!: <span class="hljs-built_in">string</span>;
}

const Type Parameters

TypeScript 5.0 introduced const type parameters for more precise inference:

<span class="hljs-comment">// Without const</span>
<span class="hljs-keyword">function</span> makeArray&lt;T&gt;(<span class="hljs-attr">items</span>: T[]) {
  <span class="hljs-keyword">return</span> items;
}
<span class="hljs-keyword">const</span> arr = <span class="hljs-title function_">makeArray</span>([<span class="hljs-string">&#x27;a&#x27;</span>, <span class="hljs-string">&#x27;b&#x27;</span>]); <span class="hljs-comment">// string[]</span>

<span class="hljs-comment">// With const</span>
<span class="hljs-keyword">function</span> makeConstArray&lt;<span class="hljs-keyword">const</span> T&gt;(<span class="hljs-attr">items</span>: T[]) {
  <span class="hljs-keyword">return</span> items;
}
<span class="hljs-keyword">const</span> constArr = <span class="hljs-title function_">makeConstArray</span>([<span class="hljs-string">&#x27;a&#x27;</span>, <span class="hljs-string">&#x27;b&#x27;</span>]); <span class="hljs-comment">// readonly [&quot;a&quot;, &quot;b&quot;]</span>

Benefits:

  • More specific literal types
  • Better autocomplete
  • Immutability by default
<span class="hljs-keyword">function</span> createConfig&lt;<span class="hljs-keyword">const</span> T <span class="hljs-keyword">extends</span> <span class="hljs-title class_">Record</span>&lt;<span class="hljs-built_in">string</span>, <span class="hljs-built_in">unknown</span>&gt;&gt;(<span class="hljs-attr">config</span>: T): T {
  <span class="hljs-keyword">return</span> config;
}

<span class="hljs-keyword">const</span> config = <span class="hljs-title function_">createConfig</span>({
  <span class="hljs-attr">apiUrl</span>: <span class="hljs-string">&#x27;https://api.example.com&#x27;</span>,
  <span class="hljs-attr">timeout</span>: <span class="hljs-number">5000</span>,
});

<span class="hljs-comment">// Type is:</span>
<span class="hljs-comment">// {</span>
<span class="hljs-comment">//   readonly apiUrl: &quot;https://api.example.com&quot;;</span>
<span class="hljs-comment">//   readonly timeout: 5000;</span>
<span class="hljs-comment">// }</span>

Exhaustive Switch Cases

TypeScript 5.0 improved switch case exhaustiveness checking:

<span class="hljs-keyword">type</span> <span class="hljs-title class_">Status</span> = <span class="hljs-string">&#x27;pending&#x27;</span> | <span class="hljs-string">&#x27;success&#x27;</span> | <span class="hljs-string">&#x27;error&#x27;</span>;

<span class="hljs-keyword">function</span> <span class="hljs-title function_">handleStatus</span>(<span class="hljs-params"><span class="hljs-attr">status</span>: <span class="hljs-title class_">Status</span></span>) {
  <span class="hljs-keyword">switch</span> (status) {
    <span class="hljs-keyword">case</span> <span class="hljs-string">&#x27;pending&#x27;</span>:
      <span class="hljs-keyword">return</span> <span class="hljs-string">&#x27;Loading...&#x27;</span>;
    <span class="hljs-keyword">case</span> <span class="hljs-string">&#x27;success&#x27;</span>:
      <span class="hljs-keyword">return</span> <span class="hljs-string">&#x27;Done!&#x27;</span>;
    <span class="hljs-keyword">case</span> <span class="hljs-string">&#x27;error&#x27;</span>:
      <span class="hljs-keyword">return</span> <span class="hljs-string">&#x27;Failed!&#x27;</span>;
    <span class="hljs-comment">// If you add a new status type, TypeScript will error here</span>
  }
}

Use satisfies never for runtime safety:

<span class="hljs-keyword">function</span> <span class="hljs-title function_">handleStatus</span>(<span class="hljs-params"><span class="hljs-attr">status</span>: <span class="hljs-title class_">Status</span></span>): <span class="hljs-built_in">string</span> {
  <span class="hljs-keyword">switch</span> (status) {
    <span class="hljs-keyword">case</span> <span class="hljs-string">&#x27;pending&#x27;</span>:
      <span class="hljs-keyword">return</span> <span class="hljs-string">&#x27;Loading...&#x27;</span>;
    <span class="hljs-keyword">case</span> <span class="hljs-string">&#x27;success&#x27;</span>:
      <span class="hljs-keyword">return</span> <span class="hljs-string">&#x27;Done!&#x27;</span>;
    <span class="hljs-attr">default</span>:
      <span class="hljs-comment">// This ensures all cases are handled</span>
      <span class="hljs-keyword">const</span> <span class="hljs-attr">_exhaustive</span>: <span class="hljs-built_in">never</span> = status;
      <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Error</span>(<span class="hljs-string">`Unhandled status: <span class="hljs-subst">${status}</span>`</span>);
  }
}

satisfies Operator

Validate types without widening them:

<span class="hljs-keyword">type</span> <span class="hljs-title class_">Color</span> = { <span class="hljs-attr">r</span>: <span class="hljs-built_in">number</span>; <span class="hljs-attr">g</span>: <span class="hljs-built_in">number</span>; <span class="hljs-attr">b</span>: <span class="hljs-built_in">number</span> } | <span class="hljs-built_in">string</span>;

<span class="hljs-comment">// Without satisfies - type is widened</span>
<span class="hljs-keyword">const</span> <span class="hljs-attr">color1</span>: <span class="hljs-title class_">Color</span> = { <span class="hljs-attr">r</span>: <span class="hljs-number">255</span>, <span class="hljs-attr">g</span>: <span class="hljs-number">0</span>, <span class="hljs-attr">b</span>: <span class="hljs-number">0</span> };
color1.<span class="hljs-property">r</span>; <span class="hljs-comment">// Error: Property &#x27;r&#x27; doesn&#x27;t exist on type &#x27;Color&#x27;</span>

<span class="hljs-comment">// With satisfies - exact type preserved</span>
<span class="hljs-keyword">const</span> color2 = { <span class="hljs-attr">r</span>: <span class="hljs-number">255</span>, <span class="hljs-attr">g</span>: <span class="hljs-number">0</span>, <span class="hljs-attr">b</span>: <span class="hljs-number">0</span> } <span class="hljs-keyword">satisfies</span> <span class="hljs-title class_">Color</span>;
color2.<span class="hljs-property">r</span>; <span class="hljs-comment">// ✓ Works! Type is { r: number; g: number; b: number }</span>

Real-world example:

<span class="hljs-keyword">type</span> <span class="hljs-title class_">Route</span> = {
  <span class="hljs-attr">path</span>: <span class="hljs-built_in">string</span>;
  <span class="hljs-attr">method</span>: <span class="hljs-string">&#x27;GET&#x27;</span> | <span class="hljs-string">&#x27;POST&#x27;</span> | <span class="hljs-string">&#x27;PUT&#x27;</span> | <span class="hljs-string">&#x27;DELETE&#x27;</span>;
  <span class="hljs-attr">handler</span>: <span class="hljs-function">(<span class="hljs-params"><span class="hljs-attr">req</span>: <span class="hljs-title class_">Request</span></span>) =&gt;</span> <span class="hljs-title class_">Response</span>;
};

<span class="hljs-keyword">const</span> routes = {
  <span class="hljs-attr">getUser</span>: {
    <span class="hljs-attr">path</span>: <span class="hljs-string">&#x27;/users/:id&#x27;</span>,
    <span class="hljs-attr">method</span>: <span class="hljs-string">&#x27;GET&#x27;</span>,
    <span class="hljs-attr">handler</span>: <span class="hljs-function">(<span class="hljs-params">req</span>) =&gt;</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Response</span>(),
  },
  <span class="hljs-attr">createUser</span>: {
    <span class="hljs-attr">path</span>: <span class="hljs-string">&#x27;/users&#x27;</span>,
    <span class="hljs-attr">method</span>: <span class="hljs-string">&#x27;POST&#x27;</span>,
    <span class="hljs-attr">handler</span>: <span class="hljs-function">(<span class="hljs-params">req</span>) =&gt;</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Response</span>(),
  },
} <span class="hljs-keyword">satisfies</span> <span class="hljs-title class_">Record</span>&lt;<span class="hljs-built_in">string</span>, <span class="hljs-title class_">Route</span>&gt;;

<span class="hljs-comment">// Autocomplete works for route names</span>
routes.<span class="hljs-property">getUser</span>.<span class="hljs-property">path</span>; <span class="hljs-comment">// ✓</span>
routes.<span class="hljs-property">getUser</span>.<span class="hljs-property">method</span>; <span class="hljs-comment">// ✓ Type is &#x27;GET&#x27;, not string</span>

Type-Only Imports and Exports

TypeScript 5.0 improved type-only imports:

<span class="hljs-comment">// Import only the type, not the value</span>
<span class="hljs-keyword">import</span> <span class="hljs-keyword">type</span> { <span class="hljs-title class_">User</span> } <span class="hljs-keyword">from</span> <span class="hljs-string">&#x27;./types&#x27;</span>;
<span class="hljs-keyword">import</span> { <span class="hljs-keyword">type</span> <span class="hljs-title class_">Product</span>, createProduct } <span class="hljs-keyword">from</span> <span class="hljs-string">&#x27;./api&#x27;</span>;

<span class="hljs-comment">// Export type-only</span>
<span class="hljs-keyword">export</span> <span class="hljs-keyword">type</span> { <span class="hljs-title class_">User</span> };

Why it matters:

  • Smaller bundles (types are erased)
  • Clearer intent
  • Better tree-shaking

Multi-Config Projects

extends arrays allow composing multiple configs:

<span class="hljs-punctuation">{</span>
  <span class="hljs-attr">&quot;extends&quot;</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">[</span>
    <span class="hljs-string">&quot;@tsconfig/node18/tsconfig.json&quot;</span><span class="hljs-punctuation">,</span>
    <span class="hljs-string">&quot;@tsconfig/strictest/tsconfig.json&quot;</span><span class="hljs-punctuation">,</span>
    <span class="hljs-string">&quot;./tsconfig.base.json&quot;</span>
  <span class="hljs-punctuation">]</span><span class="hljs-punctuation">,</span>
  <span class="hljs-attr">&quot;compilerOptions&quot;</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span>
    <span class="hljs-attr">&quot;outDir&quot;</span><span class="hljs-punctuation">:</span> <span class="hljs-string">&quot;./dist&quot;</span>
  <span class="hljs-punctuation">}</span>
<span class="hljs-punctuation">}</span>

Benefits:

  • Reusable configuration
  • Easier monorepo setup
  • Better defaults sharing

Performance Improvements

TypeScript 5.x includes major performance wins:

1. Faster Type Checking

<span class="hljs-comment">// This is now much faster in TS 5.x</span>
<span class="hljs-keyword">type</span> <span class="hljs-title class_">DeepPartial</span>&lt;T&gt; = {
  [P <span class="hljs-keyword">in</span> keyof T]?: T[P] <span class="hljs-keyword">extends</span> <span class="hljs-built_in">object</span> ? <span class="hljs-title class_">DeepPartial</span>&lt;T[P]&gt; : T[P];
};

2. Optimized Recursive Types

<span class="hljs-comment">// Complex recursive types are faster</span>
<span class="hljs-keyword">type</span> <span class="hljs-title class_">JSON</span> = <span class="hljs-built_in">string</span> | <span class="hljs-built_in">number</span> | <span class="hljs-built_in">boolean</span> | <span class="hljs-literal">null</span> | <span class="hljs-title class_">JSON</span>[] | { [<span class="hljs-attr">key</span>: <span class="hljs-built_in">string</span>]: <span class="hljs-title class_">JSON</span> };

3. Better Inference

<span class="hljs-comment">// Smarter inference reduces explicit annotations</span>
<span class="hljs-keyword">const</span> users = [
  { <span class="hljs-attr">id</span>: <span class="hljs-number">1</span>, <span class="hljs-attr">name</span>: <span class="hljs-string">&#x27;Alice&#x27;</span> },
  { <span class="hljs-attr">id</span>: <span class="hljs-number">2</span>, <span class="hljs-attr">name</span>: <span class="hljs-string">&#x27;Bob&#x27;</span> },
];

<span class="hljs-comment">// TypeScript correctly infers:</span>
<span class="hljs-comment">// { id: number; name: string }[]</span>

Practical Migration Tips

1. Enable Strict Mode Gradually

<span class="hljs-punctuation">{</span>
  <span class="hljs-attr">&quot;compilerOptions&quot;</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span>
    <span class="hljs-attr">&quot;strict&quot;</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">false</span></span><span class="hljs-punctuation">,</span>
    <span class="hljs-attr">&quot;noImplicitAny&quot;</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span><span class="hljs-punctuation">,</span>        <span class="hljs-comment">// Start here</span>
    <span class="hljs-attr">&quot;strictNullChecks&quot;</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span><span class="hljs-punctuation">,</span>      <span class="hljs-comment">// Then this</span>
    <span class="hljs-attr">&quot;strictFunctionTypes&quot;</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span><span class="hljs-punctuation">,</span>   <span class="hljs-comment">// Then this</span>
    <span class="hljs-comment">// ... enable others incrementally</span>
  <span class="hljs-punctuation">}</span>
<span class="hljs-punctuation">}</span>

2. Use @ts-expect-error for Known Issues

<span class="hljs-comment">// @ts-expect-error - Known issue, fix in next sprint</span>
<span class="hljs-keyword">const</span> result = <span class="hljs-title function_">legacyFunction</span>();

3. Leverage New Features Incrementally

<span class="hljs-comment">// Before</span>
<span class="hljs-keyword">const</span> <span class="hljs-attr">config</span>: <span class="hljs-title class_">Config</span> = {
  <span class="hljs-attr">apiUrl</span>: <span class="hljs-string">&#x27;https://api.example.com&#x27;</span>,
};

<span class="hljs-comment">// After - use satisfies for better types</span>
<span class="hljs-keyword">const</span> config = {
  <span class="hljs-attr">apiUrl</span>: <span class="hljs-string">&#x27;https://api.example.com&#x27;</span>,
} <span class="hljs-keyword">satisfies</span> <span class="hljs-title class_">Config</span>;

Advanced Patterns

1. Branded Types

<span class="hljs-keyword">type</span> <span class="hljs-title class_">UserId</span> = <span class="hljs-built_in">string</span> &amp; { <span class="hljs-attr">__brand</span>: <span class="hljs-string">&#x27;UserId&#x27;</span> };
<span class="hljs-keyword">type</span> <span class="hljs-title class_">ProductId</span> = <span class="hljs-built_in">string</span> &amp; { <span class="hljs-attr">__brand</span>: <span class="hljs-string">&#x27;ProductId&#x27;</span> };

<span class="hljs-keyword">function</span> <span class="hljs-title function_">getUser</span>(<span class="hljs-params"><span class="hljs-attr">id</span>: <span class="hljs-title class_">UserId</span></span>) { <span class="hljs-comment">/* ... */</span> }

<span class="hljs-keyword">const</span> userId = <span class="hljs-string">&#x27;user_123&#x27;</span> <span class="hljs-keyword">as</span> <span class="hljs-title class_">UserId</span>;
<span class="hljs-keyword">const</span> productId = <span class="hljs-string">&#x27;prod_456&#x27;</span> <span class="hljs-keyword">as</span> <span class="hljs-title class_">ProductId</span>;

<span class="hljs-title function_">getUser</span>(userId);      <span class="hljs-comment">// ✓</span>
<span class="hljs-title function_">getUser</span>(productId);   <span class="hljs-comment">// ✗ Type error!</span>

2. Template Literal Types

<span class="hljs-keyword">type</span> <span class="hljs-title class_">HTTPMethod</span> = <span class="hljs-string">&#x27;GET&#x27;</span> | <span class="hljs-string">&#x27;POST&#x27;</span> | <span class="hljs-string">&#x27;PUT&#x27;</span> | <span class="hljs-string">&#x27;DELETE&#x27;</span>;
<span class="hljs-keyword">type</span> <span class="hljs-title class_">Endpoint</span> = <span class="hljs-string">&#x27;/users&#x27;</span> | <span class="hljs-string">&#x27;/products&#x27;</span>;
<span class="hljs-keyword">type</span> <span class="hljs-title class_">Route</span> = <span class="hljs-string">`<span class="hljs-subst">${HTTPMethod}</span> <span class="hljs-subst">${Endpoint}</span>`</span>;

<span class="hljs-comment">// Route is:</span>
<span class="hljs-comment">// | &#x27;GET /users&#x27; | &#x27;POST /users&#x27; | &#x27;PUT /users&#x27; | &#x27;DELETE /users&#x27;</span>
<span class="hljs-comment">// | &#x27;GET /products&#x27; | &#x27;POST /products&#x27; | ...</span>

3. Conditional Types with Inference

<span class="hljs-keyword">type</span> <span class="hljs-title class_">UnwrapPromise</span>&lt;T&gt; = T <span class="hljs-keyword">extends</span> <span class="hljs-title class_">Promise</span>&lt;infer U&gt; ? U : T;

<span class="hljs-keyword">type</span> A = <span class="hljs-title class_">UnwrapPromise</span>&lt;<span class="hljs-title class_">Promise</span>&lt;<span class="hljs-built_in">string</span>&gt;&gt;;  <span class="hljs-comment">// string</span>
<span class="hljs-keyword">type</span> B = <span class="hljs-title class_">UnwrapPromise</span>&lt;<span class="hljs-built_in">number</span>&gt;;           <span class="hljs-comment">// number</span>

Tooling Recommendations

1. Type Coverage

npm install -D type-coverage
npx type-coverage --detail

Aim for >90% type coverage in new code.

2. ts-reset

Improve default type definitions:

npm install -D @total-typescript/ts-reset

<span class="hljs-comment">// tsconfig.json</span>
{
  <span class="hljs-string">&quot;include&quot;</span>: [<span class="hljs-string">&quot;./node_modules/@total-typescript/ts-reset&quot;</span>]
}

3. Type Challenges

Practice with type-challenges:

npm install -D @type-challenges/utils

Common Pitfalls

1. Over-Engineering Types

<span class="hljs-comment">// ❌ Too complex</span>
<span class="hljs-keyword">type</span> <span class="hljs-title class_">DeepReadonly</span>&lt;T&gt; = T <span class="hljs-keyword">extends</span> <span class="hljs-built_in">object</span>
  ? { <span class="hljs-keyword">readonly</span> [P <span class="hljs-keyword">in</span> keyof T]: <span class="hljs-title class_">DeepReadonly</span>&lt;T[P]&gt; }
  : T;

<span class="hljs-comment">// ✅ Use simpler approaches when possible</span>
<span class="hljs-keyword">type</span> <span class="hljs-title class_">Config</span> = <span class="hljs-title class_">Readonly</span>&lt;{
  <span class="hljs-attr">api</span>: <span class="hljs-title class_">Readonly</span>&lt;{ <span class="hljs-attr">url</span>: <span class="hljs-built_in">string</span>; <span class="hljs-attr">key</span>: <span class="hljs-built_in">string</span> }&gt;;
}&gt;;

2. Ignoring unknown vs any

<span class="hljs-comment">// ❌ Avoid any</span>
<span class="hljs-keyword">function</span> <span class="hljs-title function_">parseJSON</span>(<span class="hljs-params"><span class="hljs-attr">json</span>: <span class="hljs-built_in">string</span></span>): <span class="hljs-built_in">any</span> {
  <span class="hljs-keyword">return</span> <span class="hljs-title class_">JSON</span>.<span class="hljs-title function_">parse</span>(json);
}

<span class="hljs-comment">// ✅ Use unknown + type guards</span>
<span class="hljs-keyword">function</span> <span class="hljs-title function_">parseJSON</span>(<span class="hljs-params"><span class="hljs-attr">json</span>: <span class="hljs-built_in">string</span></span>): <span class="hljs-built_in">unknown</span> {
  <span class="hljs-keyword">return</span> <span class="hljs-title class_">JSON</span>.<span class="hljs-title function_">parse</span>(json);
}

<span class="hljs-keyword">const</span> data = <span class="hljs-title function_">parseJSON</span>(<span class="hljs-string">&#x27;{&quot;name&quot;: &quot;Alice&quot;}&#x27;</span>);
<span class="hljs-keyword">if</span> (<span class="hljs-keyword">typeof</span> data === <span class="hljs-string">&#x27;object&#x27;</span> &amp;&amp; data !== <span class="hljs-literal">null</span> &amp;&amp; <span class="hljs-string">&#x27;name&#x27;</span> <span class="hljs-keyword">in</span> data) {
  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(data.<span class="hljs-property">name</span>); <span class="hljs-comment">// Type-safe!</span>
}

3. Not Using Utility Types

<span class="hljs-comment">// ❌ Manual type transformation</span>
<span class="hljs-keyword">type</span> <span class="hljs-title class_">UserUpdate</span> = {
  <span class="hljs-attr">id</span>?: <span class="hljs-built_in">number</span>;
  <span class="hljs-attr">name</span>?: <span class="hljs-built_in">string</span>;
  <span class="hljs-attr">email</span>?: <span class="hljs-built_in">string</span>;
};

<span class="hljs-comment">// ✅ Use built-in utilities</span>
<span class="hljs-keyword">type</span> <span class="hljs-title class_">User</span> = { <span class="hljs-attr">id</span>: <span class="hljs-built_in">number</span>; <span class="hljs-attr">name</span>: <span class="hljs-built_in">string</span>; <span class="hljs-attr">email</span>: <span class="hljs-built_in">string</span> };
<span class="hljs-keyword">type</span> <span class="hljs-title class_">UserUpdate</span> = <span class="hljs-title class_">Partial</span>&lt;<span class="hljs-title class_">User</span>&gt;;

Conclusion

TypeScript 5.x brings powerful features that make the language more expressive and maintainable. By adopting decorators, const type parameters, and the satisfies operator, you can write safer, more self-documenting code.

The key is to adopt these features incrementally, understanding when they add value versus when simpler approaches suffice. TypeScript should enable better code, not complicate it.

Start with one or two features today, and gradually integrate them into your workflow. Your future self (and your team) will thank you.

👨‍💻

Jordan Patel

Web Developer & Technology Enthusiast

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