ERC-1155 multi-token standard in Blockchain / Solidity - Step-by-Step Execution

Concept Flow - ERC-1155 multi-token standard

Start Transaction

↓

Check Token ID

↓

Is Token Fungible?

Yes→Process Fungible Token Transfer

↓

Update Balances

↓

Is Token Non-Fungible?

Yes→Process NFT Transfer

↓

Emit Transfer Event

↓

Reject Invalid Token

↓

End Transaction

↓

End Transaction

This flow shows how ERC-1155 handles different token types in one transaction, checking token ID, type, updating balances, and emitting events.

Execution Sample

Blockchain / Solidity

function safeTransferFrom(address from, address to, uint256 id, uint256 amount, bytes data) public {
  require(to != address(0));
  balances[id][from] -= amount;
  balances[id][to] += amount;
  emit TransferSingle(msg.sender, from, to, id, amount);
}

Transfers a specified amount of a token ID from one address to another, updating balances and emitting a transfer event.

Execution Table

Step	Action	Variable/State	Value/Result	Notes
1	Check 'to' address is not zero	to	0xABC123... (valid)	Passes require check
2	Subtract amount from sender balance	balances[id][from]	100 -> 90	Sender had 100 tokens, now 90
3	Add amount to receiver balance	balances[id][to]	50 -> 60	Receiver had 50 tokens, now 60
4	Emit TransferSingle event	event	TransferSingle(msg.sender, from, to, id, amount)	Logs transfer details
5	End function	-	-	Transfer complete

💡 Function ends after updating balances and emitting event

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
balances[id][from]	100	90	90	90
balances[id][to]	50	50	60	60
to	0xABC123...	0xABC123...	0xABC123...	0xABC123...

Key Moments - 3 Insights

Why do we check if the 'to' address is zero before transferring?

Because sending tokens to the zero address would burn them unintentionally. The execution_table row 1 shows the require check preventing this.

How does ERC-1155 handle multiple token types in one contract?

It uses the token ID to distinguish tokens. The flow checks token ID and type before updating balances, as shown in the concept_flow.

What happens if the sender does not have enough tokens?

The subtraction in balances[id][from] would underflow and revert the transaction, stopping execution before emitting the event (not shown in this simple trace).

Visual Quiz - 3 Questions

Look at the execution_table, what is the sender's balance after step 2?

A 90

B 100

C 50

D 60

💡 Hint

Check the 'balances[id][from]' value in row 2 of the execution_table.

At which step is the TransferSingle event emitted?

A Step 2

B Step 4

C Step 3

D Step 5

💡 Hint

Look at the 'Action' column in the execution_table for event emission.

If the 'to' address was zero, what would happen?

A The balances would update incorrectly

B The transfer would proceed normally

C The require check would fail and stop execution

D The event would still emit

💡 Hint

Refer to step 1 in execution_table where the require check is performed.

Concept Snapshot

ERC-1155 allows multiple token types in one contract.
Use token ID to identify tokens.
safeTransferFrom updates balances for given ID and amount.
Check 'to' address is not zero to avoid burning.
Emit TransferSingle event after transfer.
Supports fungible and non-fungible tokens in one standard.

Full Transcript

ERC-1155 is a token standard that lets one contract manage many token types, both fungible and non-fungible. When transferring tokens, it first checks the recipient address is valid. Then it subtracts the amount from the sender's balance and adds it to the receiver's balance for the specific token ID. After updating balances, it emits a TransferSingle event to log the transfer. If the recipient address is zero, the transfer stops immediately to prevent token loss. This standard simplifies handling multiple tokens in one place.