ts-sdk-types

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Translated

Move to TypeScript type mapping in @aptos-labs/ts-sdk: u64/u128/u256 as bigint, address as string, TypeTag, functionArguments and typeArguments. Triggers on: 'typeArguments', 'functionArguments', 'Move to TypeScript', 'type mapping', 'TypeTag', 'bigint u128'.

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Added on2026-03-12

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TypeScript SDK: Types (Move ↔ TypeScript)

Purpose

Guide type mapping between Move and TypeScript when using

@aptos-labs/ts-sdk

: numeric types (especially u128/u256), address, TypeTag, and

functionArguments

/

typeArguments

.

ALWAYS

Use
bigint
for u128 and u256 – in both view results and
```
functionArguments
```
; JavaScript
```
number
```
loses precision above 2^53.
Use
string
for address in payloads – e.g.
```
"0x1"
```
or
```
accountAddress.toString()
```
; SDK accepts
```
AccountAddressInput
```
(string or AccountAddress).

Use
typeArguments
for generic Move functions – e.g. coin type

["0x1::aptos_coin::AptosCoin"]

for

coin::balance

or

coin::transfer

.

Cast view results explicitly when you know the Move return type – e.g.
```
BigInt(result[0] as string)
```
for u128.

NEVER

Do not use
number
for u128/u256 – precision loss; use
```
bigint
```
.
Do not pass raw number for large u64 in entry/view – use
```
bigint
```
if value can exceed Number.MAX_SAFE_INTEGER.
Do not omit typeArguments when the Move function has type parameters (e.g.
```
balance<CoinType>
```
).

Move → TypeScript (summary)

Move type	TypeScript type	Example
u8, u16, u32	number	`255` , `65535`
u64	number \| bigint	Prefer bigint for large values
u128, u256	bigint	`BigInt("340282366920938463463374607431768211455")`
i8..i64 (Move 2.3+)	number \| bigint	Use bigint for i64 when large
i128, i256	bigint	`BigInt("-...")`
bool	boolean	`true`
address	string	`"0x1"`
signer	—	Not passed from TS; signer is the transaction sender
vector<u8>	Uint8Array \| string (hex)	`new Uint8Array([1,2,3])` or hex
vector<T>	T[]	`[1, 2, 3]`
String	string	`"hello"`
Object<T>	string (object address)	`objectAddress.toString()`
Option<T>	T \| null	Value or `null`

functionArguments

Order and types must match the Move entry/view function parameters:

typescript

// Move: public fun transfer<CoinType>(to: address, amount: u64)
await aptos.transaction.build.simple({
  sender: account.accountAddress,
  data: {
    function: "0x1::coin::transfer",
    typeArguments: ["0x1::aptos_coin::AptosCoin"],
    functionArguments: [
      "0xrecipient...",  // address as string
      1000n,             // u64 as bigint (or number if small)
    ],
  },
});

typeArguments

For generic Move functions, pass full type strings (

address::module::StructName

):

typescript

// Move: balance<CoinType>(addr): u64
typeArguments: ["0x1::aptos_coin::AptosCoin"]

// Move: transfer<CoinType>(to, amount)
typeArguments: ["0x1::aptos_coin::AptosCoin"]

View return types

typescript

const result = await aptos.view({
  payload: {
    function: "0x1::coin::balance",
    typeArguments: ["0x1::aptos_coin::AptosCoin"],
    functionArguments: [accountAddress],
  },
});
// result is an array; u128 often returned as string in JSON
const balance = BigInt(result[0] as string);

TypeTag (advanced)

When building payloads programmatically or parsing type strings:

typescript

import { TypeTag } from "@aptos-labs/ts-sdk";

// Parser for type tag strings
import { parseTypeTag } from "@aptos-labs/ts-sdk";
const tag = parseTypeTag("0x1::aptos_coin::AptosCoin");

Use

typeArguments

as string array in simple cases; use TypeTag when the SDK API expects it.

Object / resource address in arguments

Pass object address as string (LONG or SHORT per AIP-40):

typescript

functionArguments: [
  nftObjectAddress.toString(),  // or "0x..."
  price,
]

Common mistakes

Mistake	Correct approach
Passing number for u128 amount	Use `1000000n` or `BigInt("...")`
Omitting typeArguments for coin::balance	Add `typeArguments: ["0x1::aptos_coin::AptosCoin"]`
Using result[0] as number for u128	Use `BigInt(result[0] as string)`
Wrong order of functionArguments	Match Move parameter order exactly

References

SDK:

src/transactions/typeTag/

,

src/transactions/instances/transactionArgument.ts

, view and build APIs

Pattern: TYPESCRIPT_SDK.md
Related: ts-sdk-view-and-query, ts-sdk-transactions, use-ts-sdk

ts-sdk-types

NPX Install

Tags

SKILL.md Content

TypeScript SDK: Types (Move ↔ TypeScript)

Purpose

ALWAYS

NEVER

Move → TypeScript (summary)

functionArguments

typeArguments

View return types

TypeTag (advanced)

Object / resource address in arguments

Common mistakes

References