TypeScript any Type: Syntax, Usage, and Examples

The any type tells TypeScript to stop checking a value’s type. It gives you full flexibility, but it also removes most of the safety TypeScript is known for.

How to Use the any type

You can use the any type on variables, function parameters, return values, arrays, and objects.

Basic syntax

letvalue:any;

value =42;
value ="hello";
value = {ready:true };

Once something is any, TypeScript stops complaining about “wrong” operations, because it assumes you know what you’re doing.

Typing function parameters with any

functionlogValue(input:any) {
console.log(input);
}

logValue("test");
logValue(123);
logValue({ok:true });

This can feel convenient, especially when you don’t know what shape the data will have yet.

Typing return values with any

functionparseSomething(raw:string):any {
returnJSON.parse(raw);
}

const result =parseSomething('{"name":"Mia"}');

TypeScript will not know what result contains, so it won’t protect you if you use it incorrectly.

any arrays

constmixed:any[] = [1,"two",false, {count:3 }];

This allows any type in the array, in any position.

any objects

constsettings:any = {
theme:"dark",
refreshRate:30,
};

settings.randomField ="added later";

This also bypasses property checking, so you can access or add properties freely.

When to Use the any type

Using any feels like removing the training wheels. Sometimes that’s fine, but do it for a reason.

1) Migrating JavaScript to TypeScript

A common workflow is:

1. convert .js to .ts
2. get a wall of errors
3. temporarily use any to move forward
4. replace any with real types later

Example:

letlegacyData:any =fetchOldData();

This keeps the project moving while you gradually improve types.

2) Handling messy external data

APIs can return data in surprising formats. any can act as a temporary “I’ll deal with this later” type.

constresponse:any =awaitfetch("/api/user").then((res) => res.json());

This works, but it’s risky because your app might assume fields exist when they don’t.

3) Quick experiments and prototypes

Sometimes you just want to test an idea fast, like building a quick demo or a small script.

lettemp:any ="start";
temp =99;
temp = [1,2,3];

In a prototype, this might be acceptable. In a real app, it usually turns into a future headache.

4) Working with third-party libraries without types

Some older libraries don’t ship proper TypeScript definitions.

constoldLib:any =require("some-old-library");
oldLib.doStuff();

This can unblock you, but a better long-term move is installing type definitions or writing a small wrapper.

Examples of the any type

Here are some common situations where people reach for any, plus what can go wrong.

Example 1: any hides mistakes

letproduct:any = {name:"Laptop",price:999 };

console.log(product.prcie);// no TypeScript error, but this is a typo

That typo would normally be caught instantly with proper types.

Example 2: any lets you call anything

letscore:any =10;

console.log(score.toUpperCase());// allowed by TS, crashes at runtime

TypeScript won’t stop you because any disables checks. Your users will “stop you” instead.

Example 3: any in event handlers

functionhandleClick(event:any) {
console.log(event.target.value);
}

This works, but you lose useful IntelliSense and safety. A better type would be something like MouseEvent, depending on the element.

Example 4: JSON parsing with any

const raw ='{"id":1,"name":"Sam"}';
constdata:any =JSON.parse(raw);

console.log(data.name.toUpperCase());

This might work, until the API changes and name becomes null, or doesn’t exist at all.

Example 5: any can spread fast

functionprocess(input:any) {
return input.data.value;
}

const output =process({something:"else" });

This compiles, but input.data might not exist. One any can quietly infect a whole file, because TypeScript stops warning you in places that depend on it.

Learn More About the any type

If you use any, you should also know what the safer alternatives are, and how to limit the damage.

Prefer unknown when you don’t know the type yet

unknown is similar to any, but safer. You can store anything in it, but you can’t use it until you check the type.

letinput:unknown ="hello";

if (typeof input ==="string") {
console.log(input.toUpperCase());
}

With unknown, TypeScript forces you to prove what you’re working with.

Use union types for “a few possible types”

If the value can only be one of a few types, use a union.

letid:string |number;

id =5;
id ="5";

This still gives flexibility, but you keep type checking.

Use type guards instead of any

Type guards help TypeScript narrow types safely.

typeUser = {name:string };

functionisUser(value:any): value isUser {
return value &&typeof value.name ==="string";
}

constdata:any = {name:"Aria" };

if (isUser(data)) {
console.log(data.name.toUpperCase());
}

This approach works well when dealing with external data.

Use Record<string, unknown> for flexible objects

Sometimes you want an object with unknown keys, but you still want safety.

constconfig:Record<string,unknown> = {
theme:"dark",
retries:3,
};

const theme = config["theme"];

Here, TypeScript won’t let you blindly treat theme as a string unless you check it first.

Limit any to the smallest possible area

If you must use any, keep it local.

Bad idea:

letapiResponse:any =awaitfetch("/api").then((r) => r.json());

Better idea:

const apiResponse =awaitfetch("/api").then((r) => r.json());
const user = apiResponseas {id:number;name:string };

This still has risk, but the unsafe part is smaller and easier to track.

Watch out for implicit any

TypeScript can also create any without you explicitly writing it, especially in older projects.

Example:

functionadd(a, b) {
return a + b;
}

If noImplicitAny is off in your TypeScript config, a and b become implicit any.

Common rules teams use around any

Many TypeScript codebases allow any, but with guardrails, such as:

• Only use any in migration code
• Never use any for function return types
• Always add a comment explaining why it exists
• Replace it with real types before merging a feature

That might sound strict, but it saves you from waking up three months later thinking, “Who wrote this, and why is everything a mystery?”

Summary

The any type disables type checking, which can make TypeScript feel like plain JavaScript. Use it when you truly need it, like during migrations, prototypes, or working with unknown third-party code.

For most cases, safer options like unknown, union types, or type guards give you flexibility without giving up the main benefit of TypeScript.