am_counter_increment: Increment a counter value

In automerge: R Bindings for 'Automerge' 'CRDT' Library

Increment a counter value

Description

Increments an Automerge counter by the specified delta. Counters are CRDT types that support concurrent increments from multiple actors. Unlike regular integers, counter increments are commutative and do not conflict when merged.

Usage

am_counter_increment(doc, obj, key, delta)

Arguments

doc	An Automerge document
obj	An Automerge object ID (map or list), or AM_ROOT for the document root
key	For maps: a character string key. For lists: an integer index (1-based)
delta	Integer value to add to the counter (can be negative)

Details

The delta can be negative to decrement the counter.

Value

The document (invisibly), allowing for chaining with pipes

Examples

# Counter in document root (map)
doc <- am_create()
doc$score <- am_counter(0)
am_counter_increment(doc, AM_ROOT, "score", 10)
doc$score  # 10

am_counter_increment(doc, AM_ROOT, "score", 5)
doc$score  # 15

# Decrement with negative delta
am_counter_increment(doc, AM_ROOT, "score", -3)
doc$score  # 12

# Counter in a nested map
doc$stats <- am_map(views = am_counter(0))
stats_obj <- doc$stats
am_counter_increment(doc, stats_obj, "views", 100)

# Counter in a list (1-based indexing)
doc$counters <- list(am_counter(0), am_counter(5))
counters_obj <- doc$counters
am_counter_increment(doc, counters_obj, 1, 1)  # Increment first counter
am_counter_increment(doc, counters_obj, 2, 2)  # Increment second counter

am_close(doc)

automerge documentation built on Feb. 5, 2026, 5:08 p.m.