// Use when configuring walkerOS event mappings for specific use cases. Provides recipes for GA4, Meta, custom APIs, and common transformation patterns.
Use when adding read-through caching to a walkerOS store, memoizing a slow API/Sheets backing, composing multi-tier cache chains, or deduplicating concurrent store reads. Covers recipes, TTL choice, error policy, and observability counters.
Use when transforming walkerOS events in the flow (source→collector or collector→destination), configuring data/map/loop/set/condition/policy, or using $code: syntax in JSON configs.
Use when bundling walkerOS flows, testing events with simulate/push, running local servers, validating configs, or configuring Flow JSON files.
Use when wiring `@walkeros/transformer-ga4` into a server flow, overriding default GA4 event mappings, dropping events, adding custom event keys, or troubleshooting GA4 Measurement Protocol decoding. Covers the `before`-chain wiring contract, configuration recipes, and per-field patching with extend/remove.
Use when writing or updating walkerOS documentation - README, website docs, or skills. Covers quality standards, example validation, and DRY patterns.
Use when learning walkerOS architecture, understanding data flow, or designing composable event pipelines. Covers Source→Collector→Destination pattern and separation of concerns.
| name | walkeros-mapping-configuration |
| description | Use when configuring walkerOS event mappings for specific use cases. Provides recipes for GA4, Meta, custom APIs, and common transformation patterns. |
Read understanding-mapping first for core concepts.
| I want to... | Use this pattern |
|---|---|
| Rename event | { name: 'new_name' } |
| Extract nested value | 'data.nested.value' |
| Set static value | { value: 'USD' } |
| Transform value | { fn: (e) => transform(e) } |
| Build object | { map: { key: 'source' } } |
| Process array | { loop: ['source', { map: {...} }] } |
| Gate by consent | { key: 'data.email', consent: { marketing: true } } |
| First defined value (fallback) | [{ key: 'data.sku' }, { key: 'data.id' }] |
| Add a field to a default rule | { extend: { data: { map: { x: 'path' } } } } |
| Drop a field from output | { remove: ['field.path'] } |
Product view → view_item:
product: {
view: {
name: 'view_item',
data: {
map: {
currency: { value: 'USD' },
value: 'data.price',
items: {
loop: [
'nested',
{
map: {
item_id: 'data.id',
item_name: 'data.name',
item_category: 'data.category',
price: 'data.price',
quantity: { value: 1 },
},
},
],
},
},
},
},
}
Order complete → purchase:
order: {
complete: {
name: 'purchase',
data: {
map: {
transaction_id: 'data.orderId',
value: 'data.total',
currency: 'data.currency',
items: {
loop: [
'nested',
{
map: {
item_id: 'data.id',
item_name: 'data.name',
price: 'data.price',
quantity: 'data.quantity',
},
},
],
},
},
},
},
}
Product view → ViewContent:
product: {
view: {
name: 'ViewContent',
data: {
map: {
content_ids: { fn: (e) => [e.data.id] },
content_type: { value: 'product' },
content_name: 'data.name',
value: 'data.price',
currency: { value: 'USD' },
},
},
},
}
Order complete → Purchase:
order: {
complete: {
name: 'Purchase',
data: {
map: {
content_ids: { fn: (e) => e.nested?.map((n) => n.data.id) ?? [] },
content_type: { value: 'product' },
value: 'data.total',
currency: 'data.currency',
num_items: { fn: (e) => e.nested?.length ?? 0 },
},
},
},
}
Transform to REST API format:
'*': {
'*': {
name: { fn: (e) => `${e.entity}_${e.action}` }, // page_view
data: {
map: {
eventName: 'name',
eventData: 'data',
userId: 'user.id',
sessionId: 'user.session',
timestamp: 'timestamp',
metadata: {
map: {
consent: 'consent',
globals: 'globals',
},
},
},
},
},
}
Different mapping based on event data:
order: {
complete: [
// High-value orders get extra tracking
{
condition: (e) => (e.data?.total ?? 0) > 500,
name: 'high_value_purchase',
data: {
map: {
value: 'data.total',
priority: { value: 'high' },
notify: { value: true },
},
},
},
// Standard orders
{
name: 'purchase',
data: { map: { value: 'data.total' } },
},
],
}
extend / remove)Some packages (such as @walkeros/transformer-ga4) ship default mapping rules.
Normally a user rule at the same key replaces the default in full. Use extend
or remove to patch instead.
Two layers, two keywords:
extend runs at init (config layer): deep-merges a partial rule onto the
shipped default. A null value clears an inherited field.remove runs after evaluation (output layer): strips dotted paths from
the final data payload. Applied last, always wins.A rule with neither keyword keeps the existing replace behavior.
{
"purchase": {
"extend": {
"data": { "map": { "affiliation": "params.ep.affiliation" } }
},
"remove": ["currency"]
}
}
This keeps all fields the package ships for purchase, adds affiliation, and
strips currency from the output.
For the full reference and the two-layer model, see Mapping.Rule docs.
At any value position, an array of values is a fallback chain: the first entry that resolves to a defined value wins.
{
"item_id": [
{ "key": "data.sku" },
{ "key": "data.id" },
{ "value": "unknown" }
]
}
Use this to try multiple source fields before falling back to a constant.
Only include PII if consent granted:
user: {
login: {
name: 'login',
data: {
map: {
method: 'data.method',
// Only include email if marketing consent
email: {
key: 'user.email',
consent: { marketing: true },
},
// Only include user ID if functional consent
userId: {
key: 'user.id',
consent: { functional: true },
},
},
},
},
}
Catch-all for unmatched events:
// Any product action
product: {
'*': {
name: { fn: (e) => `product_${e.action}` },
data: 'data',
},
}
// Any click on any entity
'*': {
click: {
name: 'element_click',
data: {
map: {
element_type: 'entity',
element_id: 'data.id',
},
},
},
}
Transform HTTP input to walkerOS event:
// In source config
{
mapping: {
// Map incoming field names to walkerOS structure
name: { fn: (input) => `${input.entity} ${input.action}` },
data: 'payload',
user: {
map: {
id: 'userId',
session: 'sessionId',
},
},
},
}
'data.nested.field'e.data?.price ?? 0nested array exists and has itemsReference: