MIGRATION.md

Nominal Changes

These are changes to the way things are named, but the functionality remains the same. This list is not exhaustive.

TEALScript	PuyaTS	Notes
GlobalStateKey	GlobalState
LocalStateKey	LocalState
BoxKey	BoxRef
prefix	keyPrefix	The prefix option for BoxMap
this.txn	Txn
this.app	Global.currentApplicationId
isOptedInToApp, isOptedInToAsset	isOptedIn	The Puya function accepts a union of these types
size	length	The size of a box

Minor Changes

These are minor changes to the syntax of the language/API. This list is not exhaustive.

TEALScript	PuyaTS	Notes
this.boxRef.create(boxSize)	this.boxRef.create({ size: boxSize })	The size option is now a property of the create method
Explcicit method return types are required	Implicit method return types are allowed
verify...Txn	assertMatch	assertMatch accepts any object. This means, however, that txn types must be explicitly checked if the verified fields apply to more than one txn type
Methods, classes, and types are in global scope	Methods, classes, and types must be imported
forEach is supported	forEach is not supported, but for ... of is supported	for ... of also enables continue/break

Major Changes

These are major changes to the syntax of the language/API.

Method Routing

TEALScript

Each action (OnCompletes and create) has a method name that is used to route to the correct method when that action/OC is performed.

createApplication() {

Alternatively, decorators can be used for more complex contracts

@allow.create('NoOp')
myCustomCreateMethod() {

PuyaTS

Decorators must be used to specify the action/OC.

@abimethod({ onCreate: "require", allowActions: "NoOp" })
createApplication() {

Math Typing

TEALScript

TEALScript supports math operators on any uint<n> type and returns the result as the same type.

getSum(x: uint64, y: uint64): uint64 {
    const sum = x + y;
    return sum;
}

PuyaTS

PuyaTS requires explicit usage of a constructor or type hint to return the result of a math operation. This is required so TypeScript (and thus your IDE and other tooling) knows the type of the result is not number (which is unavoidable TypeScript behavior).

getSum(x: uint64, y: uint64): uint64 {
    const sum = Uint64(x + y);
    return sum;
}

or

getSum(x: uint64, y: uint64): uint64 {
    const sum: uint64 = x + y;
    return sum;
}

As Casting

TEALScript

TEALScript allows casting between types using the as keyword.

const x: uint8 = 10;
const y = x as uint64;

PuyaTS

PuyaTS does not support casting between types with as. Instead, the respective constructor must be used.

const x: uint8 = 10;
const y = UintN<64>(x);

String vs Bytes

TEALScript

In TEALScript, bytes and strings are the same type and can be used interchangeably.

assert(swapAsset.assetName === "SWAP");

PuyaTS

In PuyaTS, bytes and strings are distinct types. Most functions acccept bytes | string, but outputs will always be bytes

assert(swapAsset.assetName === Bytes("SWAP"));

Array Mutability

TEALScript

TEALScript supports mutable native TypeScript arrays

const myArray: uint64[] = [1, 2, 3];
myArray.push(4);

PuyaTS

In PuyaTS native arrays are always immutable.

let myArray: uint64[] = [1, 2, 3];
myArray = [...myArray, 4];

If you want mutability, there is an explcit MutableArray type:

let myArray = new MutableArray<uint64>(1, 2, 3]);
myArray.push(4);

This type, however, can only be used internally. It cannot be put in storage, events, scratch, or used as a public ABI method parameter/return type.

Object Mutability

TEALScript

In TEALScript, objects are mutable

type Favorites {
    color: string,
    number: uint64,
}

updateFavoriteNumber(n: uint64) {
    this.favorites(this.txn.sender).value.number = n;

PuyaTS

Like Arrays, all objects are immutable.

type Favorites {
    color: string,
    number: uint64,
}

updateFavoriteNumber(n: uint64) {
    this.favorites.set(
        Txn.sender, 
        { ...this.listings.get(Txn.sender),  number: n }
    );