Array Methods

Array methods allow you to search, filter, and count elements in transaction data arrays. Blocklight supports two methods: .any() and .count().

Supported Arrays

Array	Description	Always Available?
`tx.logs`	Event logs with automatic parsing for known events	✅ Yes

`.any()` Method

Check if any element in an array matches a condition.

Syntax

array.any(field operator value)

Examples

# Detect any Transfer event (specific)
condition: tx.logs.any(event_name == "Transfer")

# Detect any Transfer category event (broader - includes all transfer variants)
condition: tx.logs.any(event_category == "Transfer")

# Detect event from specific contract
condition: tx.logs.any(address == "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48")

# Detect Transfer event to burn address (padded format)
condition: tx.logs.any(event_name == "Transfer" and to == "0x0000000000000000000000000000000000000000000000000000000000000000")

# Detect any Approval category event (includes Approval and ApprovalForAll)
condition: tx.logs.any(event_category == "Approval" and spender == "0x0000000000000000000000001234567890123456789012345678901234567890")

`.count()` Method

Count how many elements match a condition, then compare the count.

Syntax

array.count(field operator value) comparison number

Supported Comparisons

> - Greater than
< - Less than
>= - Greater than or equal
<= - Less than or equal
== - Equal to
!= - Not equal to

Examples

# Multiple Transfer events (specific)
condition: tx.logs.count(event_name == "Transfer") > 5

# Multiple Transfer category events (broader)
condition: tx.logs.count(event_category == "Transfer") > 5

# Exactly one Approval (specific)
condition: tx.logs.count(event_name == "Approval") == 1

# Any Approval category event (broader - includes ApprovalForAll)
condition: tx.logs.count(event_category == "Approval") > 0

# Multiple Transfer events to burn address
condition: tx.logs.count(event_name == "Transfer" and to == "0x0000000000000000000000000000000000000000000000000000000000000000") > 1

# Count Approval category events
condition: tx.logs.count(event_category == "Approval" and spender != "") > 3

Combining with Other Conditions

Array methods work seamlessly with logical operators (and, or, not):

# Event AND value check
condition: tx.logs.any(event_name == "Transfer") and tx.value > 100 ether

# Multiple conditions
condition: tx.logs.count(event_name == "Transfer" and to == "0x0...") > 5 and tx.gas_used > 1000000

# NOT with array method
condition: not tx.logs.any(event_name == "Approval")

Available Fields in Arrays

`tx.logs` Fields

Raw Fields (always available):

Field	Type	Description	Example
`address`	address	Contract that emitted the log	`tx.logs.any(address == "0x...")`
`event_signature`	string	Event signature hash (topic[0])	`tx.logs.any(event_signature == "0xddf...")`
`event_name`	string	Parsed event name	`tx.logs.any(event_name == "Transfer")`
`event_category`	string	Event category (group of related events)	`tx.logs.any(event_category == "Transfer")`
`data`	string	Log data (hex string)	`tx.logs.any(data != "0x")`
`log_index`	uint	Index of the log in the transaction	`tx.logs.any(log_index == 0)`
`block_number`	uint64	Block number where the log was emitted	`tx.logs.any(block_number > 18000000)`
`tx_index`	uint	Transaction index in the block	`tx.logs.any(tx_index == 5)`
`removed`	bool	Whether the log was removed	`tx.logs.any(removed == false)`

Parsed Fields (automatically added for known events): For Transfer events (event_name == "Transfer"):

Field	Type	Description	Example
`contract`	address	Token contract address	`tx.logs.any(event_name == "Transfer" and contract == "0x...")`
`from`	address	Source address (padded 32 bytes)	`tx.logs.any(event_name == "Transfer" and from == "0x0000...")`
`to`	address	Destination address (padded 32 bytes)	`tx.logs.any(event_name == "Transfer" and to == "0x0000...")`
`amount`	string	Transfer amount (hex string)	`tx.logs.any(event_name == "Transfer" and amount != "0x0")`

For Approval events (event_name == "Approval"):

Field	Type	Description	Example
`contract`	address	Token contract address	`tx.logs.any(event_name == "Approval" and contract == "0x...")`
`owner`	address	Owner address (padded 32 bytes)	`tx.logs.any(event_name == "Approval" and owner == "0x0000...")`
`spender`	address	Spender address (padded 32 bytes)	`tx.logs.any(event_name == "Approval" and spender == "0x0000...")`
`amount`	string	Approval amount (hex string)	`tx.logs.any(event_name == "Approval" and amount == "0xffff...")`

Automatic Parsing: When Blocklight recognizes an event (Transfer, Approval), it automatically parses and adds the relevant fields (from, to, amount, etc.) to the log entry. This means you can use tx.logs.any(event_name == "Transfer" and to == "0x...") directly.Recognized Events: Transfer, Approval, ApprovalForAll, Swap, UnknownEvent Categories: Transfer, Approval, Swap (more categories will be added as we expand event recognition)When to Use event_name vs event_category:

Use event_name when you need a specific event (e.g., only Transfer, not ApprovalForAll)
Use event_category when you want to detect any event in a category (e.g., all approval-related events)

Address Format: Parsed addresses (from, to, owner, spender) are padded to 32 bytes (64 hex characters) as they appear in event topics. See Fields for details.

Limitations

Not Supported

❌ Direct array index access:

# NOT SUPPORTED
tx.logs[0].address == "0x..."

❌ Complex nested conditions inside array methods:

# NOT SUPPORTED - Use separate .any() calls instead
tx.logs.any(event_name == "Transfer" and (amount > 100 or from == "0x..."))

Workarounds

For complex conditions, use multiple .any() or .count() calls:

# Instead of nested logic inside .any():
condition: >
  tx.logs.any(event_name == "Transfer") and
  tx.logs.any(address == "0x...")

Common Patterns

Token Burn Detection

- rule: Token Burn Detected
  desc: Detects ERC-20 token burns
  tags: ["token", "burn"]
  condition: >
    tx.logs.any(event_name == "Transfer" and to == "0x0000000000000000000000000000000000000000000000000000000000000000")
  output: "Token burn detected in tx %tx.hash (from=%tx.logs.matched.from amount=%tx.logs.matched.amount)"
  priority: NOTICE
  enabled: true

Multiple Transfers

- rule: Multiple Token Transfers
  desc: Detects transactions with many token transfers
  tags: ["token", "transfers"]
  condition: tx.logs.count(event_name == "Transfer" and from != "") > 10
  output: "Multiple transfers detected in tx %tx.hash"
  priority: NOTICE
  enabled: true

Welcome

Rules

Deployment

CLI Tools

Features

Production

Supported Arrays

`.any()` Method

Syntax

Examples

`.count()` Method

Syntax

Supported Comparisons

Examples

Combining with Other Conditions

Available Fields in Arrays

`tx.logs` Fields

Limitations

Not Supported

Workarounds

Common Patterns

Token Burn Detection

Multiple Transfers

Next Steps

Fields

Examples

​Supported Arrays

​.any() Method

​Syntax

​Examples

​.count() Method

​Syntax

​Supported Comparisons

​Examples

​Combining with Other Conditions

​Available Fields in Arrays

​tx.logs Fields

​Limitations

​Not Supported

​Workarounds

​Common Patterns

​Token Burn Detection

​Multiple Transfers

​Next Steps

Fields

Examples

Supported Arrays

`.any()` Method

Syntax

Examples

`.count()` Method

Syntax

Supported Comparisons

Examples

Combining with Other Conditions

Available Fields in Arrays

`tx.logs` Fields

Limitations

Not Supported

Workarounds

Common Patterns

Token Burn Detection

Multiple Transfers

Next Steps